Usmle First Aid Biochemistry

Front 1

What is the charge on DNA?

Back 1

negative

Front 2

How many subunits make up a nucleosome core?

Back 2

Eight; two of each of the four histone types

Front 3

How many times does the DNA loop around each octamer (nucleosome core)?

Back 3

twice

Front 4

What is the charge on DNA?

Back 4

negative

Front 5

What histone type is found between the nucleosome cores (the histone octamers)?

Back 5

H1

Front 6

What molecule ties the nucleosomes together in a string?

Back 6

H1 histone

Front 7

How many subunits make up a nucleosome core?

Back 7

Eight; two of each of the four histone types

Front 8

How many times does the DNA loop around each octamer (nucleosome core)?

Back 8

twice

Front 9

What histone type is found between the nucleosome cores (the histone octamers)?

Back 9

H1

Front 10

What molecule ties the nucleosomes together in a string?

Back 10

H1 histone

Front 11

During what stage of cell division does DNA condense?

Back 11

mitosis

Front 12

What is the charge on nucleosomes?

Back 12

positive

Front 13

True or False: When DNA is condensed, it is transcriptionally active.

Back 13

False; condensed DNA (heterochromatin) is transcriptionally inactive

Front 14

What are the names of the four subunits of a nucleosome core?

Back 14

H2A, H2B, H3 and H4

Front 15

Which is less condensed: heterochromatin or euchromatin?

Back 15

euchromatin

Front 16

What is DNA called when it is condensed and transcriptionally inactive?

Back 16

heterochromatin

Front 17

True or False: H1 is the only histone that is not found at the nucleosome core.

Back 17

true

Front 18

What is transcriptionally active DNA called?

Back 18

euchromatin

Front 19

How many hydrogen bonds are there between adenine and thymine?

Back 19

two

Front 20

What are the two purines?

Back 20

Adenine and Guanine (PURe As Gold)

Front 21

Which is stronger: a guanine-cytosine bond or an adenine-thymine bond?

Back 21

A guanine-cytosine bond, because it has three hydrogen bonds; an adenine-thymine bond only has two

Front 22

What are the three pyrimidines?

Back 22

Cytosine (C), thymine (T), and uracil (U) (remember, CUT the PY [pie]: PYrimidines)

Front 23

What physical property do nucleic acids with increasing proportions of guanine-cytosine bonds display?

Back 23

higher melting temperature--takes more heat to break the more stable three hydrogen bonds that connect C - G

Front 24

How many rings do pyrimidine molecules have?

Back 24

1 ring

Front 25

What nucleotide has a ketone?

Back 25

guanine

Front 26

Which three amino acids are necessary for purine synthesis?

Back 26

glycine, aspartate, and glutamine

Front 27

How many rings do purine molecules have?

Back 27

two rings

Front 28

What does deamination of cytosine yield?

Back 28

uracil

Front 29

Nucleoside = _____ + ribose

Back 29

nitrogen base

Front 30

In what type of nucleic acid is uracil found?

Back 30

RNA

Front 31

What type of bond links nucleotides?

Back 31

3' to 5' phosphodiester bond

Front 32

In what type of nucleic acid is thymine found?

Back 32

DNA

Front 33

What nucleotide has a methyl group?

Back 33

thymine (remember THYmine has a meTHYl group)

Front 34

How many hydrogen bonds are there between guanine and cytosine?

Back 34

three

Front 35

Nucleotide = _____ + phosphate

Back 35

nucleoside (nitrogenous base + ribose)

Front 36

What are the two precursors to creating the pyrimidine ring?

Back 36

aspartate and carbamoyl phosphate

Front 37

In de novo nucleotide synthesis, _____ (purines/pyrimidines) are made from IMP precursors, while _____ (purines/pyrimidines) are made from orotate precursors.

Back 37

purines; pyrimidines

Front 38

What is the quality of trimethoprim that makes it a good antibiotic?

Back 38

it inhibits bacterial dihydrofolate reductase preventing bacterial DNA synthesis (cannot make thymine)

Front 39

Pyrimides are made from orotate precursor, with _____ added later.

Back 39

PPRP (phosphoribosyl pyrophosphatase)

Front 40

What enzyme converts ribonucleotides to deoxyribonucleotides?

Back 40

ribonucleotide reductase

Front 41

Why are 6-mercaptopurine, 5-fluorouracil, methotrexate, and hydroxyurea effective antineoplastic agents?

Back 41

They interfere with nucleotide synthesis, hindering the ability of neoplastic cells to synthesize DNA

Front 42

_____ are synthesized first and converted to deoxyribonucleotides by ribonucleotide reductase.

Back 42

ribonucleotides

Front 43

Name four drugs that interfere with pyrimidine synthesis.

Back 43

methotrexate, 5-fluorouracil, trimethoprim, and hydroxyurea

Front 44

dUMP is converted to dTMP by which enzyme?

Back 44

thymidylate synthase

Front 45

What is the cofactor in the thymidylate synthase reaction?

Back 45

methyl tetrahydrofolate- The reaction requires N5N10 methylene THF

Front 46

_____ regenerates THF by reducing its oxidized form, _____.

Back 46

dihydrofolate reductase; dihydrofolate (DHF)

Front 47

Converting carbamoyl phosphate into orotic acid requires _____.

Back 47

aspartate

Front 48

Converting PRPP into IMP requires ______,______,______, and ______.

Back 48

glycine, aspartate, glutamine, and tetrahydrofolate (remember these are amino acids needed to make purines, and THF is needed to make any DNA)

Front 49

Of the 5 nucleotides (A, C, G, T, U), which is not first made in a monophosphate form?

Back 49

cytosine, UDP is converted to CTP

Front 50

6-Mercaptopurine (6-MP) blocks de novo ______ (purine/pyrimidine) synthesis.

Back 50

purine

Front 51

Treatment with 5-fluorouracil, methotrexate, or trimethoprim all affect nucleotide synthesis how?

Back 51

decreasing dTMP (thymidine) synthesis

Front 52

What enzyme does hydroxyurea inhibit?

Back 52

ribonucleotide reductase

Front 53

5-Fluorouracil inhibits ______ _____, while methotrexate and trimethoprim both inhibit ______ _____.

Back 53

thymidylate synthase; dihydrofolate reductase

Front 54

Deficiency in ornithine transcarbamoylase leads to what?

Back 54

hyperammonemia (since this enzyme is required in the urea cycle) and increased orotic acid

Front 55

Deficiency in either orotic acid phosphoribosyltransferase or orotidine 5' phosphate decarboxylase can lead to what?

Back 55

orotic aciduria- characterized by increased orotic acid in the urine, megaloblastic anemia (due to impaired DNA synthesis) and failure to thrive -- there is NO hyperammonemia as neither of these enzymes is involved in the urea cycle. (cannot convert orotic acid to UMP--problem with pyrimidine synthesis)--

Front 56

What findings are seen in orotic aciduria?

Back 56

increased orotic acid in the urine, megaloblastic anemia (due to impaired DNA synthesis) and failure to thrive -- there is NO hyperammonemia (as there is in ornithine transcarbAMoylase (OTC) deficiency)

Front 57

What is the treatment for orotic aciduria?

Back 57

uridine supplement

Front 58

What is called when a purine is substituted for a pyrimidine or when a pyrimidine is substituted for a purine?

Back 58

transversion

Front 59

What is it called when one purine is substituted for the other purine or when one pyrimidine is substituted for the other pyrimidine?

Back 59

transition

Front 60

What term refers to the fact that each codon in the genetic code specifies only a single amino acid?

Back 60

unambiguous

Front 61

Where might you see a genetic code that has overlapping genes?

Back 61

some viruses

Front 62

What does it mean that the genetic code is "degenerate"?

Back 62

there are more than one codon that code for the same amino acid

Front 63

True or False: The genetic code is universal.

Back 63

true; although there are a few exceptions in archaic life forms)

Front 64

What does a commaless, nonoverlapping genetic code entail?

Back 64

The entire genome is read from a fixed starting point as a continuous string of bases

Front 65

True or False: Methionine is encoded by more than one codon.

Back 65

False; methionine is encoded by only 1 codon (AUG)

Front 66

Methionine is encoded by which codon?

Back 66

AUG = start codon

Front 67

List four exceptions to the rule that the genetic code is universal.

Back 67

mitochondria, archaebacteria, mycoplasma, and some yeasts

Front 68

Rank the following types of mutations in order of severity: missense, silent, nonsense.

Back 68

most severe: nonsense (codes for stop codon) > missense > silent (least severe-no affect)

Front 69

What is it called when a mutation in DNA results in no change to the amino acid that is being coded for?

Back 69

Silent mutation

Front 70

Silent mutations are often the result of changes in what position of a codon?

Back 70

The third position (tRNA wobble)

Front 71

What is it called when a DNA mutation yields a changed amino acid?

Back 71

missense mutation

Front 72

What kind of mutation is a DNA change that results in the misreading of all nucleotides downstream of it?

Back 72

frameshift mutation

Front 73

What does it mean if a missense mutation is "conservative"?

Back 73

The new amino acid has a similar chemical structure as the originally intended one

Front 74

A frameshift mutation tends to yield what?

Back 74

A truncated, nonfunctional protein

Front 75

What is a "nonsense mutation"?

Back 75

A DNA change that results in an early-stop codon

Front 76

What is the purpose of DNA topoisomerases creating a nick in the DNA helix?

Back 76

to relieve tension/supercoils in front of the replication fork-- allowing helicase to continue unzipping

Front 77

What type of nucleic acid does primase read from?

Back 77

DNA

Front 78

How many origins of replication does prokaryotic DNA use? eukaryotic?

Back 78

one; multiple

Front 79

What is the function of primase?

Back 79

It makes an RNA primer on which DNA polymerase III can then initiate replication

Front 80

What type of nucleic acid does primase build with?

Back 80

RNA

Front 81

Which enzymes has exonuclease activity in prokaryotic DNA replication?

Back 81

DNA polymerase III (3'--> 5' exonuclease) and DNA polymerase I (5'--> 3' exonuclease)

Front 82

In which direction does DNA polymerase III have exonuclease activity?

Back 82

3'--> 5' (it is looking over it's shoulder at the last base it put down to make sure it is correct--proofreading)

Front 83

What enzyme elongates the chain by building on an RNA primer?

Back 83

DNA polymerase III

Front 84

When does DNA polymerase III "proofread" the DNA?

Back 84

After adding each nucleotide, it "proofreads" it

Front 85

Can DNA polymerase III initiate replication without an RNA primer?

Back 85

no

Front 86

What enzyme degrades the RNA primer during prokaryotic DNA replication?

Back 86

DNA polymerase I (5' --> 3' exonuclease)

Front 87

In which direction does DNA polymerase III synthesize DNA?

Back 87

5' --> 3'

Front 88

In what direction does DNA polymerase I excise the RNA primers?

Back 88

5' --> 3'

Front 89

What enzymes create a nick in the helix?

Back 89

DNA topoisomerases (e.g. DNA gyrase)

Front 90

True or False: DNA replication is semiconservative.

Back 90

true; semiconservative DNA replication produces 2 double helices each composed of one original DNA strand and one new DNA strand

Front 91

Is the leading strand synthesized continuously or discontinuously?

Back 91

continuously

Front 92

Onto which end of the newly synthesized DNA molecule does DNA polymerase III add the next subunit?

Back 92

3'

Front 93

Is the lagging strand synthesized continuously or discontinuously?

Back 93

dicontinuously

Front 94

What enzyme seals pieces together during prokaryotic DNA replication?

Back 94

DNA ligase

Front 95

When does DNA polymerase III stop adding deoxynucleotides to the 3' end?

Back 95

When it reaches the primer of the preceding fragment

Front 96

Which drug category inhibits DNA gyrase (a specific prokaryotic topoisomerase)?

Back 96

fluoroquinolones

Front 97

What enzyme has 3' → 5' exonuclease activity?

Back 97

DNA polymerase III

Front 98

What enzyme has proofreading activity in prokaryotic DNA replication?

Back 98

DNA polymerase III

Front 99

What is the name of the Y-shaped region along the DNA template where leading and lagging strands are synthesized?

Back 99

replication fork

Front 100

Which protein unwinds the DNA template at the replication fork?

Back 100

DNA helicase

Front 101

Where does eukaryotic DNA replication begin?

Back 101

origin of replication - a consensus sequence that is rich in AT bases

Front 102

What prevents DNA strands from re-annealing once helicase has separated them?

Back 102

single stranded DNA binding proteins

Front 103

What are the pieces that are formed in discontinuously synthesized DNA called?

Back 103

okazaki fragments

Front 104

DNA polymerase I and III are (prokaryotic / eukaryotic) enzymes.

Back 104

prokaryotic - but there are analogues is eukaryotes

Front 105

What enzyme has 5' → 3' exonuclease activity?

Back 105

DNA polymerase I

Front 106

True or False: Eukaryotic DNA has more than one origin of replication.

Back 106

true

Front 107

True or False: The excision-repair-specific glycosylase works on both strands of DNA at once.

Back 107

False; it is a single-strand, excision-specific glycosylase

Front 108

During nucleotide excision DNA repair, what kind of enzyme first makes a break in the damaged DNA?

Back 108

endonuclease

Front 109

During nucleotide excision repair, what is the function of the specific endonuclease?

Back 109

removes oligonucleuotides containing damaged base

Front 110

True or False: The single-strand, excision-repair-specific glycosylase can recognize damaged bases.

Back 110

true

Front 111

True or False: The single-strand, excision-repair-specific glycosylase can remove damaged bases.

Back 111

true

Front 112

True or False: Xeroderma pigmentosum is caused by defects in DNA repair.

Back 112

true it is caused by defects in nucleotide excision repair which is supposed to correct thymidine dimers that were created by UV damage

Front 113

What is the specific defective DNA repair mechanism in xeroderma pigmentosa?

Back 113

nucleotide excision repair

Front 114

During nucleotide excision DNA repair, what enzyme seals the junctions between fragments?

Back 114

DNA ligase

Front 115

What is the difference between single- and double-strand DNA repair as it relates to DNA homology?

Back 115

Double-strand DNA repair is non-homologous and simply attaches fragment ends together, while single-strand repair maintains homology

Front 116

True or False: Eukaryotic DNA has more than one origin of replication.

Back 116

true

Front 117

True or False: The excision-repair-specific glycosylase works on both strands of DNA at once.

Back 117

False; it is a single-strand, excision-specific glycosylase

Front 118

During nucleotide excision DNA repair, what kind of enzyme first makes a break in the damaged DNA?

Back 118

endonuclease

Front 119

During nucleotide excision repair, what is the function of the specific endonuclease?

Back 119

removes oligonucleuotides containing damaged base

Front 120

True or False: The single-strand, excision-repair-specific glycosylase can recognize damaged bases.

Back 120

true

Front 121

True or False: The single-strand, excision-repair-specific glycosylase can remove damaged bases.

Back 121

true

Front 122

True or False: Xeroderma pigmentosum is caused by defects in DNA repair.

Back 122

true it is caused by defects in nucleotide excision repair which is supposed to correct thymidine dimers that were created by UV damage

Front 123

What is the specific defective DNA repair mechanism in xeroderma pigmentosa?

Back 123

nucleotide excision repair

Front 124

During nucleotide excision DNA repair, what enzyme seals the junctions between fragments?

Back 124

DNA ligase

Front 125

What is the difference between single- and double-strand DNA repair as it relates to DNA homology?

Back 125

Double-strand DNA repair is non-homologous and simply attaches fragment ends together, while single-strand repair maintains homology

Front 126

Patients with xeroderma pigmentosum show excessive sensitivity to what? What organ is most affected?

Back 126

Ultraviolet light; the skin

Front 127

What process brings together two nonhomologous ends of DNA and seals them together?

Back 127

Nonhomologous end joining, which is a type of double-stranded DNA repair

Front 128

With what pattern is xeroderma pigmentosa inherited?

Back 128

autosomal recessive

Front 129

The phrase "children of the night" describes patients with _____ ______ due to an increased risk for melanoma and other cancers with exposure to sunlight.

Back 129

xeroderma pigmentosum

Front 130

Xeroderma pigmentosa results in an inability to repair what specific DNA error?

Back 130

thymidine dimers

Front 131

What commonly causes thymidine dimers to form in DNA?

Back 131

UV light exposure

Front 132

What cancer is xeroderma pigmentosa associated with?

Back 132

melanoma

Front 133

True or False: Xeroderma pigmentosum is associated with dry skin.

Back 133

true

Front 134

What is the first step in the base excision repair of damaged DNA?

Back 134

Specific glycosylases recognize and remove a single damaged base

Front 135

In base excision repair, what does the apurinic/apyrimidinic endonuclease do?

Back 135

It cuts the DNA at a apyrimidinic site and removes the empty sugar

Front 136

In base excision repair, what enzyme fills the gap?

Back 136

DNA polymerase

Front 137

In single-stranded DNA repair, how are nucleotide excision and base excision repair different?

Back 137

During nucleotide repair, the entire nucleotide structure is removed and replaced; during base excision repair, the base is clipped off of the sugar and repaired without the whole backbone of the DNA being taken apart

Front 138

In single-stranded DNA mismatch repair, how does the repair mechanism recognize the new strand (and thereby avoid replacing bases on the original template strand of DNA)?

Back 138

The mismatch repair mechanism recognizes the template (and, therefore, the older strand) by its degree of methylation
-- older strands are methylated

Front 139

In single-stranded DNA repair, how is mismatch repair different from nucleotide excision and base excision repair?

Back 139

Mismatch repair changes a mismatched nucleotide (using the degree of methylation to tell the new and old strands of DNA apart), whereas the other two types both repair damaged DNA (as opposed to mismatched DNA)

Front 140

Hereditary nonpolyposis colon cancer results from loss of what DNA repair mechanism?

Back 140

DNA mismatch repair

Front 141

What is the name of the method of double-stranded DNA repair?

Back 141

nonhomologous end joining

Front 142

A child presents to your office with dry skin and has a history of several skin cancers including melanoma; what is the likely diagnosis?

Back 142

xeroderma pigmentosum- defect in nucleotide excision repair of thymidine dimers caused by UV light

Front 143

In what direction is DNA synthesized?

Back 143

From 5' to 3'

Front 144

During DNA and RNA synthesis, what ion group is found at the 5′ end of the incoming nucleoside?

Back 144

A triphosphate (two of the phosphates get cleaved off to produce the energy needed for the incoming nucleotide to bind to the previous nucleotide via its 3' Carbon on ribose)

Front 145

True or False: During RNA synthesis, the triphosphate bond provides the energy source for the formation of the new phosphodiester bond.

Back 145

true

Front 146

In what direction is RNA synthesized?

Back 146

From 5' to 3'

Front 147

True or False: During DNA synthesis, the triphosphate bond provides the energy source for the formation of the new phosphodiester bond.

Back 147

true

Front 148

In what direction does protein synthesis proceed?

Back 148

N terminus to C terminus of the amino acids

Front 149

During DNA and RNA synthesis, what is the target of the incoming nucleotide?

Back 149

The 3' hydroxyl of the nascent chain (carbon on the ribose)

Front 150

During protein synthesis amino acids are linked from _____ to _____.

Back 150

N to C creating peptide bonds between adjacent amino acids

Front 151

What type of RNA is the largest?

Back 151

mRNA (m = massive)

Front 152

What type of RNA is the most abundant?

Back 152

rRNA (r = rampant)

Front 153

What type of RNA is the smallest?

Back 153

tRNA (t = tiny)

Front 154

In prokaryotes, the initial AUG codes for what amino acid?

Back 154

formyl Methionine (fMet)

Front 155

What codon is the mRNA initiation codon?

Back 155

AUG (or, rarely, GUG) (remember, AUG inAUGurates protein synthesis)

Front 156

In eukaryotes, AUG codes for what amino acid?

Back 156

methionine (Met)

Front 157

True or False: After completing translation, all eukaryotic proteins have a methionine at one end.

Back 157

False; the initial methionine can be removed before translation is complete

Front 158

During the process of eukaryotic protein synthesis, when can the initial methionine removed?

Back 158

before translation is complete

Front 159

List three stop codons.

Back 159

UGA, UAA, UAG (remember U Go Away, U Are Away, and U Are Gone)

Front 160

What is the name of the DNA site at which RNA polymerase and multiple other transcription factors bind?

Back 160

promoter

Front 161

What are the elements that make up the promoter region?

Back 161

The promoter region is an AT-rich sequence with TATA and CAAT boxes

Front 162

Is a promoter upstream or downstream of its gene locus?

Back 162

upstream

Front 163

In addition to RNA polymerase, what else binds to a promoter?

Back 163

transcription factors

Front 164

What is the name for a DNA site where negative regulators (repressors) bind?

Back 164

silencers

Front 165

What commonly results from a mutation within a promoter?

Back 165

decreased transcription

Front 166

What is the name for a stretch of DNA that alters gene expression by binding transcription factors?

Back 166

enhancer

Front 167

True or False: An enhancer that regulates expression can be located close to, far from, or within the intron of the gene that it regulates.

Back 167

True

Front 168

If an enhancer is located within the gene that it regulates, in what part of the gene is it typically found?

Back 168

in an intron

Front 169

What is the name for a negative regulator of gene expression?

Back 169

repressor

Front 170

In eukaryotes, what enzyme makes rRNA?

Back 170

RNA polymerase I

Front 171

True or False: In eukaryotes, RNA polymerases have a proofreading function.

Back 171

false; RNA polymerases have no proofreading function in eukaryotes (DNA polyermase III has proofreading ability)

Front 172

What poisonous protein, which inhibits RNA polymerase II, is found in death cap mushrooms?

Back 172

alpha-amanitin

Front 173

True or False: In eukaryotes, RNA polymerases can initiate chains.

Back 173

true; no primer is needed as there is in DNA replication/synthesis

Front 174

In eukaryotes, which RNA polymerase opens DNA at the promoter site?

Back 174

RNA polymerase II

Front 175

What are the sites at which RNA polymerase II opens DNA called?

Back 175

promoter sites

Front 176

In eukaryotes, what enzyme makes mRNA?

Back 176

RNA polymerase II

Front 177

In eukaryotes, what enzyme makes tRNA?

Back 177

RNA polymerase III

Front 178

In prokaryotes, what enzyme makes rRNA?

Back 178

RNA polymerase -- there is only one type

Front 179

In prokaryotes, what enzyme makes mRNA?

Back 179

RNA polymerase -- there is only one type

Front 180

In prokaryotes, what enzyme makes tRNA?

Back 180

RNA polymerase-- there is only one type

Front 181

Where does eukaryotic RNA processing occur?

Back 181

in the nucleus-- the RNA must be fully processed-- capped, tailed and spliced before it can go out into the cytoplasm

Front 182

List the three parts of eukaryotic RNA processing.

Back 182

Capping on the 5' end with 7-methylguanosine, polyadenylation on the 3' end, and splicing out of the introns

Front 183

What gets placed on the 5′ end during the process of capping?

Back 183

7-methyl guanosine

Front 184

After which event during protein synthesis does eukaryotic RNA processing occur?

Back 184

transcription

Front 185

On what end of mRNA does polyadenylation occur?

Back 185

3' end (tail)

Front 186

On what end of mRNA does capping occur?

Back 186

5' end (head)

Front 187

About how many As get added to the 3' end of mRNA during polyadenylation?

Back 187

200

Front 188

What gets added to the 3′ end during polyadenylation?

Back 188

about 200 Adenines (As)

Front 189

True or False: Initial RNA transcripts are called heterogeneous nuclear RNA.

Back 189

true hnRNA = preRNA = before processing

Front 190

True or False: Processed RNA can be transported out of the nucleus.

Back 190

true

Front 191

True or False: After RNA transcripts have been capped and tailed, they are called hnRNA.

Back 191

False; this is mRNA, while the initial transcript is called hnRNA

Front 192

What is the polyadenylation signal?

Back 192

AAUAAA

Front 193

True or False: Unprocessed RNA is never transported out of the nucleus.

Back 193

true

Front 194

True or False: Poly-A polymerase requires a template.

Back 194

False; it just sees it polyadenylation signal and lays down a ton of As

Front 195

True or False: The splicing of introns out of a primary mRNA transcript is done in a precise manner.

Back 195

true

Front 196

What gets spliced out of primary mRNA transcripts?

Back 196

introns

Front 197

What binds to a primary mRNA transcript and forms a spliceosome?

Back 197

Small nuclear ribonucleoprotein particles (snRNPs) and other proteins

Front 198

What is the shape of the intermediate that is formed during mRNA splicing?

Back 198

lariat = lasso

Front 199

What particles facilitate the splicing of mRNA?

Back 199

small nuclear ribonuclear proteins (snRNPs)

Front 200

What does a small nuclear ribonucleoprotein particle form after binding a 1° mRNA transcript?

Back 200

splicosome

Front 201

What is the name of the portions of a gene that contain the actual genetic information coding for the protein?

Back 201

exon

Front 202

True or False: The formation of mRNA from pre-mRNA involves splicing.

Back 202

true

Front 203

What is the name for the intervening noncoding segments of DNA within a gene?

Back 203

introns

Front 204

Different exons within a single gene can be combined by ____ _____ to make unique proteins in different tissues.

Back 204

alternative splicing

Front 205

True or False: The formation of mRNA from DNA involves transcription.

Back 205

true

Front 206

Beta-thalassemia occurs due to a mutation causing splicing defects in a process that combines different exons within a single gene. What is this process called?

Back 206

alternative splicing

Front 207

Other than aminoacyl-tRNA synthetase, what else is responsible for the accuracy of amino acid selection?

Back 207

The binding of charged tRNA to the correct codon

Front 208

How many nucleotides make up the structure of an average tRNA?

Back 208

75-90-- it is the smallest type of RNA

Front 209

True or False: If a tRNA gets mischarged and is not caught by aminoacyl-tRNA synthetase when it checks for errors, then the mischarged tRNA reads the usual codon.

Back 209

True; it reads the usual codon but inserts a different amino acid

Front 210

What shape is a tRNA?

Back 210

cloverleaf form

Front 211

What part of a tRNA lies opposite from its 3' aminoacyl end?

Back 211

the anticodon end

Front 212

What three-nucleotide sequence do all eukaryotic tRNAs have at their 3' ends?

Back 212

CCA

Front 213

Where in tRNA is there a high percentage of chemically modified bases?

Back 213

at the 3' end

Front 214

What is the energy source for tRNA?

Back 214

ATP

Front 215

Where on a tRNA does the amino acid bind?

Back 215

the 3' end

Front 216

During the process of charging tRNA, ATP gets converted to what?

Back 216

AMP and pyrophosphate (PPi)

Front 217

If a tRNA had a methionine bound to it, what would the sequence of the codon it binds read? (Give this in order from the 5' end to the 3' end.) What would its anticodon sequence read? (Give this in the same order.)

Back 217

5' AUG 3' codon
5' CAU 3' anticodon

it would look like this
3' UAC 5' tRNA anticodon
5' AUG 3' mRNA codon

Front 218

What enzyme charges tRNA by adding an amino acid to it?

Back 218

aminoacyl tRNA synthetase

Front 219

If a tRNA gets paired up and bound to an incorrectly matched amino acid and the error is caught when it gets checked, what happens to the amino tRNA-amino acid?

Back 219

The bond between them gets hydrolyzed by the aminoacyl-tRNA synthetase enzyme

Front 220

What are the substrates of the reaction that is catalyzed by aminoacyl-tRNA synthetase?

Back 220

an uncharged tRNA, appropriate amino acid, and ATP

Front 221

What does the reaction that is catalyzed by aminoacyl-tRNA synthetase yield?

Back 221

A charged tRNA (a tRNA with the appropriate amino acid covalently bound), adenosine monophosphate, and pyrophosphate (AMP and PPi)

Front 222

List the enzyme that scrutinizes the match between a tRNA and its amino acid.

Back 222

aminoacyl tRNA synthetase (scrutinizes the aa before and after putting it on)

Front 223

During protein synthesis, the energy to form a peptide bond comes directly from which bond?

Back 223

From the aminoacyl-tRNA bond

Front 224

At what points during amino acid attachment does aminoacyl-tRNA synthetase check the match between a tRNA and its amino acid?

Back 224

Both before and after it binds the tRNA

Front 225

What enzyme is responsible for hydrolyzing the bond between an incorrectly matched tRNA and amino acid?

Back 225

aminoacyl tRNA synthetase

Front 226

With what kind of chemical bond connects a tRNA attach to its amino acid?

Back 226

covalent bond

Front 227

How does tetracycline interfere with protein translation?

Back 227

tetracycline binds to the 30S subunit of the ribosome preventing aminoacyl tRNA from binding

Front 228

True or False: Accuracy in the first nucleotide position of an mRNA codon is required for proper protein synthesis.

Back 228

true

Front 229

True or False: Accuracy in the third nucleotide position of an mRNA codon is required for proper protein synthesis.

Back 229

false; due to degeneracy of the genetic code, many times the 3rd base won't change the amino acid that is made

Front 230

What is the third nucleotide position of an mRNA codon sometimes called?

Back 230

the wobble position

Front 231

True or False: Codons differing in the third nucleotide may code for the same tRNA/amino acid.

Back 231

true

Front 232

Different codons that code for the same tRNA/amino acid can differ in which position?

Back 232

3rd/wobble position

Front 233

_____ (Eukaryotes/prokaryotes) have ribosomes with 60S and 40S subunits.

Back 233

Eukaryotes (Even numbers)

Front 234

What are the sizes of the two subunits of the eukaryotic ribosome called?

Back 234

40S and 60S subunits

Front 235

When referring the "A site" of a ribosome, what does the "A" stand for?

Back 235

aminoacyl-- where incoming tRNA-aa sits down

Front 236

List the positions (sites) on a ribosome starting from the 5' end of a bound mRNA and going toward the 3' end.

Back 236

E, P, A

Front 237

At the start of protein synthesis, after the incoming amino acid binds to the A site, what happens to the bond between methionine and its tRNA?

Back 237

it gets hydrolyzed

Front 238

_____ (Eukaryotes/prokaryotes) have ribosomes with 50S and 30S subunits.

Back 238

prokaryotes

Front 239

At the start of protein synthesis, methionine sits in which site on the ribosome?

Back 239

in the P site

Front 240

At the start of protein synthesis, what process occurs at the same time as the hydrolysis of methionine's bond with its tRNA?

Back 240

The formation of a peptidyl bond between methionine and the second amino acid in the polypeptide

Front 241

When referring the "P site" of a ribosome, what does the "P" stand for?

Back 241

peptidyl

Front 242

What happens to the ribosome after the formation of a peptidyl bond?

Back 242

it advances 3 bases in the 3' direction on the mRNA

Front 243

During protein synthesis, the incoming amino acid binds to which site on the ribosome?

Back 243

A site

Front 244

True or False: Initiation factors (eIFs) for protein synthesis are activated by GTP hydrolysis.

Back 244

true

Front 245

In what direction relative to the mRNA does the ribosome shift after the formation of a peptidyl bond?

Back 245

toward the 3' end

Front 246

When the ribosome shifts after the formation of a peptidyl bond, in what position does the tRNA with the growing peptide chain end up?

Back 246

the P site

Front 247

What molecule provides the energy for the charging of tRNA?

Back 247

ATP

Front 248

What molecule provides the energy for the binding of tRNA to the ribosome/mRNA complex?

Back 248

GTP

Front 249

What molecule provides the energy for the translocation of the ribosome along the mRNA?

Back 249

GTP

Front 250

In protein synthesis, when are the initiation factors released?

Back 250

When mRNA is bound to the ribosomal complex

Front 251

In protein synthesis, what is the first step of elongation?

Back 251

Aminoacyl-tRNA binds to the A site

Front 252

In protein synthesis, what is the second step of elongation?

Back 252

Peptidyltransferase adds the growing peptide to the amino acid at site A

Front 253

In protein synthesis, what is the third step of elongation?

Back 253

The ribosome advances three nucleotides in the 3' direction, thereby moving the tRNA with the growing peptide chain to the P site ?

Front 254

In protein synthesis, what happens during termination?

Back 254

The completed protein is released from the ribosome, which disassociates

Front 255

When the ribosome shifts after the formation of a peptidyl bond, where is the uncharged tRNA found?

Back 255

the E position

Front 256

What is the order of the positions of the ribosome that the tRNA occupies during translation?

Back 256

A, P, E (think of "going APE")

Front 257

In protein synthesis, what is the role of initiation factors?

Back 257

To assemble the 40S ribosomal subunit with the initiatior tRNA

Front 258

In protein synthesis, what are the three steps of protein elongation?

Back 258

(1) Aminoacyl-tRNA binds to the A site; (2) peptidyltransferase adds a peptide to the amino acid chain at site A; and (3) the ribosome advances three nucleotides in the 3′ direction, thereby moving the tRNA to the P site

Front 259

In protein synthesis, the A site of the ribosome holds what?

Back 259

The incoming Aminoacyl-tRNA

Front 260

In protein synthesis, the P site of the ribosome holds what?

Back 260

The growing Peptide chain

Front 261

In protein synthesis, the E site of the ribosome holds what?

Back 261

The Empty tRNA as it exits the ribosome

Front 262

How do aminoglycosides interfere with protein synthesis?

Back 262

They inhibit formation of the initiation complex, causing misreading of mRNA

Front 263

During protein synthesis, the incoming amino acid binds to which site on the ribosome?

Back 263

A site

Front 264

True or False: Initiation factors (eIFs) for protein synthesis are activated by GTP hydrolysis.

Back 264

true

Front 265

In what direction relative to the mRNA does the ribosome shift after the formation of a peptidyl bond?

Back 265

toward the 3' end

Front 266

When the ribosome shifts after the formation of a peptidyl bond, in what position does the tRNA with the growing peptide chain end up?

Back 266

the P site

Front 267

What molecule provides the energy for the charging of tRNA?

Back 267

ATP

Front 268

What molecule provides the energy for the binding of tRNA to the ribosome/mRNA complex?

Back 268

GTP

Front 269

What molecule provides the energy for the translocation of the ribosome along the mRNA?

Back 269

GTP

Front 270

In protein synthesis, when are the initiation factors released?

Back 270

When mRNA is bound to the ribosomal complex

Front 271

In protein synthesis, what is the first step of elongation?

Back 271

Aminoacyl-tRNA binds to the A site

Front 272

In protein synthesis, what is the second step of elongation?

Back 272

Peptidyltransferase adds the growing peptide to the amino acid at site A

Front 273

In protein synthesis, what is the third step of elongation?

Back 273

The ribosome advances three nucleotides in the 3' direction, thereby moving the tRNA with the growing peptide chain to the P site ?

Front 274

In protein synthesis, what happens during termination?

Back 274

The completed protein is released from the ribosome, which disassociates

Front 275

When the ribosome shifts after the formation of a peptidyl bond, where is the uncharged tRNA found?

Back 275

the E position

Front 276

What is the order of the positions of the ribosome that the tRNA occupies during translation?

Back 276

A, P, E (think of "going APE")

Front 277

In protein synthesis, what is the role of initiation factors?

Back 277

To assemble the 40S ribosomal subunit with the initiatior tRNA

Front 278

In protein synthesis, what are the three steps of protein elongation?

Back 278

(1) Aminoacyl-tRNA binds to the A site; (2) peptidyltransferase adds a peptide to the amino acid chain at site A; and (3) the ribosome advances three nucleotides in the 3′ direction, thereby moving the tRNA to the P site

Front 279

In protein synthesis, the A site of the ribosome holds what?

Back 279

The incoming Aminoacyl-tRNA

Front 280

In protein synthesis, the P site of the ribosome holds what?

Back 280

The growing Peptide chain

Front 281

In protein synthesis, the E site of the ribosome holds what?

Back 281

The Empty tRNA as it exits the ribosome

Front 282

How do aminoglycosides interfere with protein synthesis?

Back 282

They inhibit formation of the initiation complex, causing misreading of mRNA

Front 283

What enzyme is affected by chloramphenicol?

Back 283

chloramphenicol inhibits the 50S peptidyltransferase

Front 284

Where do macrolides and clindamycin bind and what does this cause?

Back 284

bind the 50S ribosome subunit and block translocation-- movement of the tRNA with the growing polypeptide chain to the P site

Front 285

What is the result of clindamycin binding to the 50S subunit?

Back 285

blocks translocation of tRNA

Front 286

Why are antibiotics such as chloramphenicol, clindamycin, and macrolides selective for bacteria?

Back 286

They affect the 50S subunit of the ribosome, which is found in prokaryotic cells

Front 287

What conversion occurs with the breakage of 2 phosphoanhydride bonds from ATP?

Back 287

ATP to AMP

Front 288

True or False: The conversion of ATP to AMP occurs in tRNA aminoacylation.

Back 288

true

Front 289

Loading tRNA onto the ribosome is associated with the conversion of GTP to _____.

Back 289

GDP

Front 290

Translocation is associated with the conversion of _____ (ATP/GTP) to _____ (ADP/GDP).

Back 290

GTP to GDP

Front 291

What is the total energy expenditure required in the addition of a single amino acid to a protein in translation?

Back 291

4 high energy phosphoanhydride bonds

Front 292

Trimming is what kind of posttranslational protein modification?

Back 292

The removal of N- or C- terminal propeptides from zymogens (inactive enzyme precursor) to generate mature proteins

Front 293

Covalent alterations involve what kinds of posttranslational protein modifications?

Back 293

Phosphorylation, glycosylation, and hydroxylation

Front 294

"Proteosomal degradation" involves what kind of posttranslational protein modification?

Back 294

The attachment of ubiquitin to defective proteins to tag them for breakdown

Front 295

In protein synthesis, what is a zymogen?

Back 295

An immature peptide in which the of N- or C-terminal propeptides have not been trimmed

Front 296

Phosphorylation, glycosylation, and hydroxylation of a protein result in the formation of what kind of bond?

Back 296

covalent

Front 297

What form of covalent modification is commonly used to regulate enzymes?

Back 297

phosphorylation

Front 298

True or False: The feedback inhibition of enzymes is an example of allosteric regulation.

Back 298

true

Front 299

True or False: The action of steroid hormones is an example of the transcriptional regulation of enzymes.

Back 299

true

Front 300

List five ways that enzymes are regulated.

Back 300

Enzyme concentration changes (synthesis and/or destruction), covalent modification, proteolytic modification, allosteric regulation, and transcriptional modification

Front 301

What is a precursor enzyme that is regulated by proteolytic modification commonly called?

Back 301

a zymogen

Front 302

List the four main phases of mitosis in order.

Back 302

Prophase--> metaphase--> anaphase--> telophase (PMAT)

Front 303

True or False: Mitosis occurs during the S phase of the cell cycle.

Back 303

False; mitosis occurs after G2 and before G1 in the cell cycle

Front 304

During which phase of the cell cycle can a cell enter G0?

Back 304

G1

Front 305

When a cell comes out of G0, what phase of the cell cycle is it in?

Back 305

G1

Front 306

Which phase of the cell cycle is usually the shortest?

Back 306

mitosis

Front 307

Which phase of the cell cycle is shortened in rapidly dividing cells?

Back 307

G1

Front 308

Phase-specific _____ activate CDKs, which are constitutive and inactive.

Back 308

cyclins

Front 309

Phase-specific cyclins activate ____, which are constitutive and inactive.

Back 309

CDKs (cyclin dependent kinases)

Front 310

Permanent and stable cells are typically in which phase of the cell cycle?

Back 310

G0

Front 311

True or False: Mitosis occurs during the S phase of the cell cycle.

Back 311

False; mitosis occurs after G2 and before G1 in the cell cycle

Front 312

Checkpoints that control transitions between phases are regulated by which three factors?

Back 312

Cyclins, CDKs, and tumor suppressor genes

Front 313

True or False: Cyclin-CDK complexes must be both activated and inactivated for cell cycle to progress.

Back 313

true

Front 314

During which phase of the cell cycle can a cell enter G0?

Back 314

G1

Front 315

When a cell comes out of G0, what phase of the cell cycle is it in?

Back 315

G1

Front 316

Which phase of the cell cycle is usually the shortest?

Back 316

mitosis

Front 317

Which phase of the cell cycle is shortened in rapidly dividing cells?

Back 317

G1

Front 318

Phase-specific _____ activate CDKs, which are constitutive and inactive.

Back 318

cyclins

Front 319

Phase-specific cyclins activate ____, which are constitutive and inactive.

Back 319

CDKs (cyclin dependent kinases)

Front 320

Permanent and stable cells are typically in which phase of the cell cycle?

Back 320

G0

Front 321

Checkpoints that control transitions between phases are regulated by which three factors?

Back 321

Cyclins, CDKs, and tumor suppressor genes

Front 322

True or False: Cyclin-CDK complexes must be both activated and inactivated for cell cycle to progress.

Back 322

true

Front 323

Rb and p53 tumor suppressors normally inhibit which cell cycle phase?

Back 323

G1--> S transition

Front 324

_____ (Permanent/stable/labile) cells remain in G0 and regenerate from stem cells.

Back 324

permanent

Front 325

_____ (Permanent/stable/labile) cells enter G1 from G0 when stimulated.

Back 325

stable

Front 326

_____ (Permanent/stabl/labile) cells never go to G0 and divide rapidly with a short G1.

Back 326

labile- always dividing

Front 327

True or False: Stable cells regenerate from stem cells.

Back 327

False; permanent cells regenerate from stem cells, stable cells are stimulated to enter G1 from g0

Front 328

Neurons, skeletal and cardiac muscle, and RBCs are examples of _____ (permanent/stable/labile) cells.

Back 328

permanent

Front 329

Hepatocytes and lymphocytes are examples of _____ (permanent/stable/labile) cells .

Back 329

stable

Front 330

What type of cell never enters the G0 phase?

Back 330

labile cells (skin, hair, gut epithelium, bone marrow)

Front 331

Bone marrow, gut epithelium, skin, and hair follicles are examples of _____ (permanent/stable/labile) cells.

Back 331

labile

Front 332

Neurons, skeletal and cardiac muscle cells, and RBCs remain in which cell cycle phase?

Back 332

G0

Front 333

What happens to cell cycling when you have a mutation in a tumor suppressor such as Rb or p53?

Back 333

There is unrestrained growth in the cell, and thus an increased likelihood to develop a malignancy

Front 334

List the four main phases of the cell cycle in order.

Back 334

Mitosis--> G1--> S--> G2

Front 335

List the three components of interphase.

Back 335

G1, S, G2

Front 336

In what phases of the cell cycle does growth occur?

Back 336

G1 and G2

Front 337

What organelle is the site of the synthesis of secretory proteins?

Back 337

rough endoplasmic reticulum

Front 338

What are the main functions of the rough endoplasmic reticulum?

Back 338

The synthesis of secretory (exported) proteins and the addition of N-linked oligosaccharides to proteins

Front 339

Which type of sugar moiety is commonly added to proteins in the rough endoplasmic reticulum?

Back 339

N-linked oligosaccharides

Front 340

Give an example of a cell of the gastrointestinal tract that is rich in rough endoplasmic reticulum.

Back 340

mucus secreting goblet cells

Front 341

Give an example of a hematologic cell that is rich in rough endoplasmic reticulum.

Back 341

plasma cells-- constantly making Ab proteins

Front 342

What histologic finding is consistent with RER in neurons?

Back 342

nissl bodies, which are the site of enzyme (e.g. Choline Acetyltransferase) and peptide neurotransmitters

Front 343

Which organelle is not attached to any membrane and serves as the site of synthesis of cytosolic and organellar proteins?

Back 343

free ribosomes

Front 344

_____ (Free/attached) ribosomes synthesize cytosolic and organellar proteins, whereas _____ (free/attached) ribosomes synthesize secretory proteins.

Back 344

free; attached

Front 345

List two functions of the smooth endoplasmic reticulum.

Back 345

detoxification and steroid synthesis

Front 346

You are working a night shift in the ED when an infant comes in after getting into the medicine cabinet. Your resident turns to you and asks, "which hepatocyte organelle will likely detoxify these drugs?"

Back 346

smooth endoplasmic reticulum

Front 347

Give two examples of cells that are rich in smooth endoplasmic reticulum.

Back 347

hepatocytes and steroid-hormone producing cells of the adrenal cortex

Front 348

The Golgi apparatus functions as the distribution center for what?

Back 348

Synthesized proteins and lipids

Front 349

Proteins and lipids arrive at the Golgi apparatus from where?

Back 349

endoplasmic reticulum

Front 350

List three places to which the Golgi apparatus sends proteins and lipids.

Back 350

The plasma membrane, lysosomes, and secretory vesicles

Front 351

Clathrin is a protein that transports vesicles from the trans face of the Golgi apparatus to where?

Back 351

To the lysosome/late endosome, or to the plasma membrane

Front 352

What type of protein-bound saccharides get modified in the Golgi apparatus?

Back 352

N-oligosaccharides

Front 353

In patients with I-cell disease, the failure to add mannose-6-phosphate to proteins in the Golgi apparatus leads to what deficit?

Back 353

There is no signal that targets the lysosomal protein to the lysosome

Front 354

N-oligosaccharides bound to which amino acid get modified in the Golgi apparatus?

Back 354

asparagine

Front 355

List four common findings among patients with I-cell disease.

Back 355

coarse facial features, clouded corneas, restricted joint movement, and elevated levels of lysosomal enzymes in the plasma-- may lead to death in early childhood

Front 356

What should you inform the parents of a child who has been diagnosed with I-cell disease about the prognosis?

Back 356

Unfortunately, this disease is often fatal in childhood

Front 357

What type of saccharides get added to proteins in the Golgi apparatus?

Back 357

O-linked oligosaccharides

Front 358

COPII is associated with _____ (retrograde/anterograde) movement from the _____ _____ _____ to the cis-Golgi.

Back 358

anterograde; rough endoplasmic reticulum

Front 359

O-oligosaccharides get added to which two amino acid residues in the Golgi apparatus?

Back 359

serine and threonine

Front 360

True or False: Proteoglycans get assembled from their component core proteins in the Golgi apparatus.

Back 360

true

Front 361

By what process are sugars in proteoglycans modified in the Golgi apparatus?

Back 361

sulfation

Front 362

In addition to the sugars on proteoglycans, what else gets sulfated in the Golgi apparatus?

Back 362

selected tyrosine residues on proteins

Front 363

What gets added to specific lysosomal proteins in the Golgi apparatus?

Back 363

mannose-6-phosphate--targeting them for lysosomes

Front 364

What is the function of the addition of mannose-6-phosphate to certain proteins in the Golgi apparatus?

Back 364

It targets them to the lysosome

Front 365

What disease results from the failure of the addition of mannose-6-phosphate to lysosomal proteins?

Back 365

I cell disease

Front 366

COPI is associated with _____ (retrograde/anterograde) movement from the Golgi apparatus to the _____ _____.

Back 366

retrograde; endoplasmic reticulum

Front 367

What is the basic pathophysiologic defect in patients with I-cell disease?

Back 367

The failure of the addition of mannose-6-phosphate to lysosomal proteins

Front 368

What is the fate of lysosomal proteins in patients with I-cell disease?

Back 368

The proteins get secreted outside of the cell instead of being targeted to the lysosome

Front 369

True or False: COPI, COPII and clathrin mediate vesicular trafficking in the Golgi apparatus.

Back 369

true

Front 370

Clathrin is a protein that transports vesicles via receptor-mediated endocytosis from the plasma membrane to which organelle?

Back 370

endosome

Front 371

What is the name of the process by which clathrin transports vesicles from outside the cell to inside the cell through fusion of the two lipid-based membranes?

Back 371

receptor mediated endocytosis

Front 372

_____ (COPI/COPII) mediates retrograde transport of substances from the golgi apparatus to endoplasmic reticulum. whereas _____ (COPI/COPII) mediates anterograde transport of substances from the rough endoplasmic reticulum to cis-Golgi apparatus,

Back 372

COPI; COPII

Front 373

Is kinesin involved in transport from the cell body to the axon (anterograde transport) or from the axon to the cell body (retrograde transport)?

Back 373

cell body --> axon (anterograde)

Front 374

Microtubules are formed from what two protein building blocks?

Back 374

α-Tubulin and β-tubulin

Front 375

What syndrome results from a microtubule polymerization defect that leads to impaired lysosomal emptying and poor phagocytosis?

Back 375

Chediak Higashi syndrome

Front 376

Microtubules are found in the _____ _____, which is a structure that is important in the process of mitosis.

Back 376

mitotic spindle

Front 377

True or False: Microtubule filaments grow rapidly but collapse quickly.

Back 377

false; they grow SLOWLY but collapse rapidly

Front 378

What high-energy phosphate molecule is bound to each tubulin dimer?

Back 378

GTP (guanosine triphosphate)

Front 379

Microtubules are found in what two structures that are involved in cell motility?

Back 379

cilia and flagella

Front 380

Are microtubules involved in fast or slow transport along the neuronal axons?

Back 380

slow transport along neuronal axons

Front 381

What is the underlying defect in symptoms of Chédiak-Higashi syndrome: pyogenic infections, partial albinism, and peripheral neuropathy?

Back 381

A microtubule polymerization defect; this disrupts phagocytosis, the secretion of melanin, and axonal transport in neurons

Front 382

Is dynein involved in transport from the cell body to the axon (anterograde transport) or from the axon to the cell body (retrograde transport)?

Back 382

axon--> cell body (retrograde transport)

Front 383

How many guanosine triphosphate molecules are bound to each tubulin dimer?

Back 383

2 GTP per dimer

Front 384

What drug that is used to treat gout acts on microtubules?

Back 384

Colchicine

Front 385

What anticancer drugs block the polymerization of microtubules?

Back 385

vincristine and vinblastine

Front 386

What anticancer drug used to treat breast cancers stabilizes microtubules?

Back 386

paclitaxel (taxol)

Front 387

What antifungal agent targets microtubules?

Back 387

griseofulvin

Front 388

What antihelminthic drugs target microtubules?

Back 388

Mebendazole and Thiabendazole

Front 389

What ATPase is responsible for retrograde transport on the microtubule?

Back 389

dynein

Front 390

What ATPase is responsible for anterograde transport on the microtubule?

Back 390

kinesin

Front 391

How are cilia structurally composed?

Back 391

9 Microtubule doublets around 2 central microtubules

Front 392

What syndrome results from a defect in the dynein arm of cilia?

Back 392

kartagener's syndrome

Front 393

What is the mechanism by which cilia bend?

Back 393

Differential sliding of the peripheral microtubule doublets

Front 394

What protein causes the movement of the cilia?

Back 394

axonemal dynein ATPase that causes the bending of the cilium

Front 395

Which diagnosis should you consider in a male with infertility, bronchiectasis and recurrent sinusitis?

Back 395

Kartegener's syndrome

Front 396

True or False: Kartagener's syndrome causes only male infertility.

Back 396

False; Kartagener's syndrome causes infertility in both sexes

Front 397

A 22-year-old female presents with a 10-day history of productive cough with yellow-green sputum. Subsequent CXR reveals dextrocardia. What is the most likely diagnosis involving these two findings?

Back 397

Kartagener's syndrome

Front 398

A patient with infertility, bronchiectasis, and chronic sinus infections likely has what genetic disease that is caused by nonmotile cilia?

Back 398

kartagener's syndrome

Front 399

What is the underlying cellular malfunction that leads to Kartagener's syndrome?

Back 399

Immotile cilia as a result of a dynein arm defect

Front 400

Immotile cilia as a result of a dynein arm defect cause what symptoms?

Back 400

male and female infertility, bronciectasis, repeated sinus infections (it is associated with situs inversus)- kartagener's syndrome

Front 401

Microvilli and adherens junctions are composed of which two cytoskeletal elements?

Back 401

actin and myosin

Front 402

Which two cytoskeletal elements are necessary for muscle contraction and cytokinesis?

Back 402

actin and myosin

Front 403

Cilia, flagella, mitotic spindles, neurons and centrioles are all composed of which cytoskeletal element?

Back 403

microtubules

Front 404

Vimentin, desmin, cytokeratin, glial fibrillary acid proteins, and neurofilaments are all different types of which cytoskeletal element?

Back 404

intermediate filaments

Front 405

Approximately what percent of the plasma membrane is composed of cholesterol?

Back 405

50%

Front 406

Approximately what percent of the plasma membrane is composed of phospholipids?

Back 406

50%

Front 407

What is the effect on melting temperature if the content of cholesterol in the plasma membrane is increased?

Back 407

increased melting temperature

Front 408

What is the effect on melting temperature if the content of long-chain saturated fatty acids in the plasma membrane is decreased?

Back 408

decreased melting temperature

Front 409

Does increasing the content of cholesterol have the same or the opposite effect on melting temperature as compared with the increasing amount of long saturated fatty acids in the plasma membrane?

Back 409

It has the same effect; both increase the melting temperature

Front 410

True or False: The plasma membrane is a symmetric fluid bilayer that is composed of phospholipids, sphingolipids, glycolipids, cholesterol, and proteins.

Back 410

False; the plasma membrane is asymmetric

Front 411

What is the effect on the plasma membrane of increased long saturated fatty acid content?

Back 411

increased melting temperature and decreased fluidity

Front 412

What is the effect on the plasma membrane of increased cholesterol?

Back 412

increased melting temperature and decreased fluidity

Front 413

Vimentin stains identify which type of cells?

Back 413

connective tissue

Front 414

Desmin stains identify which type of cells?

Back 414

muscle

Front 415

Cytokeratin stains identify which type of cells?

Back 415

epithelial cells

Front 416

Neurofilament stains identify which type of cells?

Back 416

neurons

Front 417

Glial fibrillary acid protein (GFAP) stains identify which type of cells?

Back 417

neuroglia

Front 418

The ATP binding site of the Na+-K+-ATPase is on which side of the plasma membrane?

Back 418

cytosol (inside)

Front 419

Na+-K+-ATPase moves _____ (how many) Na+ ions out in exchange for _____ (how many) K+ ions in.

Back 419

3 Na+ out; 2 K+ in (against their concentration gradients)

Front 420

During the movement of Na+ across the plasma membrane, is the Na+-K+-ATPase phosphorylated or dephosphorylated?

Back 420

phosphorylated?

Front 421

What effect does the inhibition of the Na+-;K+-ATPase by digoxin or digitoxin have on cardiac contractility?

Back 421

increased cardiac contractility because calcium is stuck inside the cell since the Na+/Ca2+ gradient cannot be established

Front 422

True or False: Digoxin and digitoxin inhibit the Na+-K+-ATPase, increasing cardiac contractility.

Back 422

true

Front 423

Where does ouabain bind to the Na+-K+-ATPase?

Back 423

At the K+ binding site

Front 424

How does inhibition of Na+-K+ exchange result in increased cardiac contractility?

Back 424

There is indirect inhibition of Na+-Ca2+ exchange, which results in increased intracellular Ca2+ concentration
(sodium is not pumped out of the cell, therefore there is no gradient established for sodium to be pumped back in, while Ca2+ goes out)

Front 425

What is the most abundant type of collagen?

Back 425

type I collagen (it is #1)

Front 426

What type of collagen is found in teeth?

Back 426

dentin- type I collagen

Front 427

What type of collagen is found in bone?

Back 427

type ONE collagen in bONE

Front 428

True or False: Collagen is the most abundant protein in the human body.

Back 428

true

Front 429

True or False: A defect in collagen synthesis would result in a weakened, well-organized extracellular matrix.

Back 429

False; collagen plays an important role in the strength and organization of the extracellular matrix

Front 430

What type of collagen is found in dentin?

Back 430

type I

Front 431

What type of collagen is found in the uterus?

Back 431

type III collagen

Front 432

What type of collagen predominates in fetal tissue?

Back 432

type III collagen

Front 433

What type of collagen is found in the cornea?

Back 433

type I (cOrNEa) = ONE

Front 434

What type of collagen is found in the basal lamina?

Back 434

type IV collagen

Front 435

What type of collagen is found in the basement membrane?

Back 435

type IV collagen

Front 436

During wound healing, type ____ collagen is laid down first as part of granulation tissue. Then, type ____ collagen is produced as part of late wound healing.

Back 436

III; I

Front 437

What type of collagen is found in the skin and fascia?

Back 437

type I

Front 438

What two types of collagen are found in the skin?

Back 438

Types I and III

Front 439

What two types of collagen are found in the eye?

Back 439

Type I in cornea, type II in vitreous body

Front 440

What type of collagen is found in the vitreous body?

Back 440

type II

Front 441

What type of collagen is found in the nucleus pulposus?

Back 441

type II

Front 442

What type of collagen is found in hyaline cartilage?

Back 442

type II (carTWOlage)

Front 443

What type of collagen is found in blood vessels?

Back 443

type III

Front 444

What is another name for type III collagen?

Back 444

reticulin (reticular = net-like)

Front 445

What type of collagen is found on the articular surface of joints?

Back 445

type II

Front 446

True or False: Once collagen is translated, there is very little further modification.

Back 446

false; collagen is extensively modified

Front 447

A triple helix composed of three collagen α chains that has not yet been cleaved is referred to as what?

Back 447

procollagen

Front 448

Where does collagen synthesis occur in the cell?

Back 448

in the rough endoplasmic reticulum

Front 449

True or False: The majority of a collagen molecule is composed of a repeating tripeptide that is composed of glycine, proline, and either hydroxyproline or hydroxylysine.

Back 449

true

Front 450

True or False: Essentially every third amino acid in a collagen α chain is a glycine residue.

Back 450

Gly-X-Y where X and y are either proline, hydroxyproline, or hydroylysine,

Front 451

Which vitamin is required for the hydroxylation of proline and lysine in collagen?

Back 451

Vitamin C-- if none--> scurvy

Front 452

The conversion of preprocollagen to procollagen requires what process?

Back 452

glycosylation

Front 453

A single-collagen α chain during collagen synthesis is referred to as what?

Back 453

preprocollagen

Front 454

Where in the cell are collagen α chains hydroxylated?

Back 454

in the endoplasmic reticulum

Front 455

What form of collagen is exocytosed from the cell into the extracellular space?

Back 455

procollagen

Front 456

An -OH group is added to _____ and _____ after translation of the collagen α chain.

Back 456

proline; lysine

Front 457

What is the name of the enzyme that cleaves the terminal regions of procollagen?

Back 457

procollagen peptidase

Front 458

Where in the cell are preprocollagen molecules glycosylated?

Back 458

in the endoplasmic reticulum

Front 459

British sailors in the 17th century come to you due to an inability to hydroxylate proline and lysine residues for collagen synthesis. What disease do they have, and why do you prescribe limes?

Back 459

They have developed scurvy, and the limes will supply them with the vitamin C they are deficient in during their long voyage (and earn them the nickname, "limeys")

Front 460

A triple helix that is composed of three collagen α chains with the terminal regions cleaved off is referred to as what?

Back 460

tropocollagen (once terminal regions cleaved-->tropocollagen)

Front 461

Is tropocollagen formed intracellularly or extracellularly?

Back 461

extracellularly

Front 462

What is the name of the enzyme that covalently cross-links lysine residues to hydroxylysine residues?

Back 462

lysyl oxidase

Front 463

Many staggered tropocollagen molecules with covalent lysine-hydroxylysine cross-links are referred to as _____ _____.

Back 463

collagen fibrils

Front 464

Is lysyl oxidase found intracellularly or extracellularly?

Back 464

Extracellularly

Front 465

Does the formation of tropocollagen from the cleavage of procollagen increase or decrease its solubility?

Back 465

Decreases; tropocollagen is insoluble.

Front 466

What cell type is responsible for collagen synthesis?

Back 466

fibroblasts

Front 467

What disease results in an inability to form procollagen from pro alpha chains?

Back 467

osteogenesis imperfecta

Front 468

Ehlers-Danlos syndrome is a defect of what process?

Back 468

collagen synthesis (type III is most frequently affected)

Front 469

True or False: There are 6 types of Ehlers-Danlos syndrome.

Back 469

true

Front 470

Ehlers-Danlos syndrome is associated with what defects of the vasculature of the brain?

Back 470

berry aneurysms

Front 471

True or False: All 6 types of Ehlers-Danlos syndrome are transmitted through an autosomal recessive inheritance pattern.

Back 471

False; Ehlers-Danlos syndrome shows variable inheritance, depending on the type- may be autosomal dominant

Front 472

A patient presents with hyperextensible skin, easy bruising, and hypermobile joints. What is the most likely diagnosis?

Back 472

Ehlers Danlos syndrome

Front 473

What type of collagen is most frequently affected in Ehlers-Danlos syndrome?

Back 473

type III collagen (reticulin)

Front 474

Why might patients with Ehlers-Danlos syndrome have an increased risk of organ rupture?

Back 474

Poor type III collagen synthesis results in weak blood vessels and reticular fibers in organs

Front 475

What type of inheritance does osteogenesis imperfecta show?

Back 475

autosomal dominant

Front 476

A baby is born with multiple fractures and hearing loss. What finding is expected during the ophthalmologic examination?

Back 476

blue sclera

Front 477

True or False: The incidence of osteogenesis imperfecta is roughly 1:1,000,000

Back 477

False; the incidence is 1:10,000

Front 478

Osteogenesis imperfecta is a defect of what type of synthesis?

Back 478

collagen synthesis (mostly type I collagen)

Front 479

How is the development of blue sclerae in osteogenesis imperfecta similar to the reason these infants have brittle bones?

Back 479

Both symptoms are due to a loss of normal functioning type I collagen. The blue sclerae result from decreased connective tissue over the choroid in the eye, while multiple fractures are from weak and decreased collagen in the bone matrix

Front 480

True or False: Osteogenesis imperfecta and Ehlers-Danlos syndrome result from defects in the synthesis of the same molecule.

Back 480

true; collagen

Front 481

Which type of osteogenesis imperfecta is fatal in utero?

Back 481

type II

Front 482

True or False: Osteogenesis imperfecta is also known as brittle bone disease.

Back 482

true

Front 483

Broken bones that result from osteogenesis imperfecta may be confused with what?

Back 483

child abuse

Front 484

The dental imperfections seen in osteogenesis imperfecta is due to lack of _____ in the teeth?

Back 484

dentin (made my type I collagen)

Front 485

A young woman with blue sclerae also has hearing loss. What is the hearing loss a result of?

Back 485

abnormal ossicles (bones of the middle ear)

Front 486

What is the typical inheritance pattern of Alport's syndrome?

Back 486

X-linked recessive

Front 487

What type of collagen is disrupted in Alport's syndrome?

Back 487

type IV collagen

Front 488

Would you expect the onset of symptoms in Alport's syndrome to be rapid or progressive?

Back 488

progressive- the nephritis and deafness are progressive

Front 489

True or False: Alport's syndrome is the result of a single point mutation in the collagen IV gene.

Back 489

False; Alport's syndrome is due to a variety of gene defects

Front 490

You are seeing a man who has progressive deafness and renal failure. The other males in his family show the same symptoms; what is the likely diagnosis?

Back 490

Alport's syndrome, which is typified by progressive nephritis and deafness

Front 491

What organ (other than the kidneys and the ears) can be affected in Alport's syndrome?

Back 491

This disease may result in ocular lesions

Front 492

What is the relationship between Alport's syndrome and Goodpasture's syndrome?

Back 492

Both are diseases of type IV collagen (Alport's is genetic; Goodpasture's is autoimmune)

Front 493

What role does fibrillin (the protein that is found to be defective in patients with Marfan's syndrome) play?

Back 493

it acts a scaffold for tropoelastin

Front 494

Where is the structural role of type IV collagen?

Back 494

Type IV collagen is an important part of the basement membrane in the kidneys, eyes, and ears

Front 495

What is a stretchy protein found within lungs, large arteries, elastic ligaments, vocal cords, ligamenta flava (which connect the vertebrae)?

Back 495

elastin

Front 496

α1-Antitrypsin inhibits which enzyme?

Back 496

elastase which degrades elastin

Front 497

Excess elastase activity can result in what lung disorder?

Back 497

emphysema: α1-antitrypsin inhibits elastase, which degrades elastin; therefore, a lack of α1-antitrypsin can leads to the loss of elastin in the lungs, thereby resulting in emphysema

Front 498

True or False: Elastin has both a relaxed form and a stretched form.

Back 498

true

Front 499

Elastin is rich in which two amino acids?

Back 499

proline and glycine

Front 500

Marfan's syndrome is caused by a defect in what protein?

Back 500

fibrillin

Front 501

Proline and glycine can be found in elastin in the (glycosylated / nonglycosylated) form.

Back 501

nonglycosylated

Front 502

Is polymerase chain reaction used to amplify the number of copies of DNA fragments or of RNA fragments?

Back 502

DNA fragments

Front 503

How is the size of a DNA fragment determined from an agarose gel?

Back 503

A DNA ladder of known lengths is run alongside the PCR fragments

Front 504

How is DNA separated into two strands during polymerase chain reaction?

Back 504

it is denatured into two strands by heating

Front 505

In polymerase chain reaction, premade _____ are used to anneal to specific DNA sequences that will then be amplified.

Back 505

primers

Front 506

What enzyme is used in polymerase chain reaction to amplify DNA?

Back 506

heat-stable DNA polymerase

Front 507

True of False: The DNA polymerase used in polymerase chain reaction has to be heat stable to withstand the denaturation process that is used to separate DNA strands.

Back 507

true

Front 508

True or False: One round of DNA denaturation followed by primer binding and the replication by DNA polymerase is enough to yield a large number of copies of a desired DNA fragment.

Back 508

False; many rounds of denaturation and replication are required to yield a large number of DNA fragments

Front 509

Identify the technique: DNA is denatured by heat into two strands. DNA primers anneal to complementary sites on a strand of DNA. Heat-stable DNA polymerase replicates the segment of DNA between two primers.

Back 509

polymerase chain reaction (PCR)

Front 510

Following PCR, how can products be separated and analyzed?

Back 510

Agarose gel electrophoresis

Front 511

Which would travel further on an agarose gel: a 10-kD or an 100-kD DNA fragment?

Back 511

10 kD fragment- smaller molecules travel farther

Front 512

Does a Western blot detect specific sequences of DNA, RNA, or protein?

Back 512

protein

Front 513

Identify the technique: Sample protein is separated via gel electrophoresis and transferred to a filter. Labeled antibody is used to bind the protein of interest.

Back 513

Western Blot

Front 514

What blot technique detects specific sequences of DNA?

Back 514

Southern Blot

Front 515

How does the mnemonic "SNoW DRoP" help one remember which type of blot is used to detect DNA sequences, RNA sequences, or proteins?

Back 515

SNoW DRoP
Southern DNA
Northern RNA
Western Protein

Front 516

Does a Southern blot detect specific sequences of DNA, RNA, or protein?

Back 516

DNA

Front 517

Identify the technique: DNA is run on an electrophoresis gel and transferred to a filter. The DNA on the filter is denatured and exposed to a labeled DNA probe. The double-stranded DNA is visualized when the filter is exposed to film.

Back 517

Southern Blot

Front 518

What blot technique detects specific sequences of RNA?

Back 518

noRthern blot

Front 519

Does a Northern blot detect specific sequences of DNA, RNA, or protein?

Back 519

RNA

Front 520

Identify the technique: RNA is run on an electrophoresis gel and transferred to a filter. The RNA on the filter is exposed to a labeled DNA probe. The hybrid DNA-RNA molecule is visualized when the filter is exposed to film.

Back 520

Northern blot

Front 521

What blot technique detects specific proteins?

Back 521

Western blot

Front 522

Which assay would allow you to detect single nucleotide polymorphisms (SNPs)?

Back 522

microarrays

Front 523

How can a microarray profile gene expression levels?

Back 523

The microarray scanner can detect relative amounts of complementary binding to probes on a chip

Front 524

Identify the technique: Thousands of nucleic acid sequences are arranged in grids on glass or silicon. DNA or RNA probes are hybridized to the chip, and a scanner detects the relative amounts of complementary binding.

Back 524

microarrays

Front 525

True or False: In the microarray biology technique, DNA or RNA probes are hybridized to the chip.

Back 525

True; either DNA or RNA probes may be used- chip contains grid of a bunch of DNA sequences

Front 526

What information would an ELISA using a test antigen coupled to a color-generating enzyme give you?

Back 526

It would tell you whether a certain antibody is present in the patient's blood

Front 527

True or False: Enzyme-linked immunosorbent assay tests antigen-antibody reactivity.

Back 527

true

Front 528

What information would an ELISA using a test antibody coupled to a color-generating enzyme give you?

Back 528

It would tell you whether a certain antigen is present in the patient's blood

Front 529

True or False: Enzyme-linked immunosorbent assay is only used to detect whether an antigen is present in a patient's blood. It cannot be used to test for the presence of an antibody.

Back 529

False; it can be used to test for the presence of an antibody in a patient's blood-- there are two different techniques-one using labeled antigen to find antibody and the other using labeled anitbody to find antigen

Front 530

Identify the technique: A test antigen that is labeled with a color-generating enzyme can be used to determine the presence of a specific antibody. If the antibody is present, the solution will have an intense color reaction.

Back 530

Enzyme-Linked ImmunoSorbent Assay (ELISA)

Front 531

True or False: The sensitivity and specificity of the enzyme-linked immunosorbent assay approaches 100%.

Back 531

true; however, false-negative and false-positive results may still occur-- which is why when you get an initial HIV ELISA screening test that is positive you do a western blot to confirm the result

Front 532

What is the advantage of a FISH analysis over a karyotype?

Back 532

The FISH analysis allows researchers to identify anomalies at a molecular level, including deletions that are too small to see on a karyotype

Front 533

What allows FISH analysis to detect deletions too small to visualize on karyotype?

Back 533

The small DNA or RNA probe used in FISH analysis allows you to illuminate a difference that is too small to otherwise see under a microscope, as in karyotyping

Front 534

What laboratory technique is represented with the acronym FISH?

Back 534

Fluorescence In Situ Hybridization

Front 535

What type of probe is used in fluorescent in situ hybridization?

Back 535

A fluorescent probe binds to a site of genetic interest

Front 536

What does fluorescent in situ hybridization allow researchers to do?

Back 536

Directly visualize the location of a certain protein or gene on a molecular level through a fluorescent probe that binds to a site of interest-- can see translocations, deletions, etc

Front 537

What does DNA cloning produce?

Back 537

A recombinant DNA molecule that is self-perpetuating

Front 538

In cloning, DNA fragments are inserted into bacterial plasmids containing genes coding for what?

Back 538

antibiotic resistance

Front 539

In cloning, what is the significance of inserting DNA to be replicated into plasmids also containing antibiotic-resistance genes and then growing the bacteria on media containing the antibiotic that bacteria is resistant to?

Back 539

This technique selects for replication of the plasmid containing genes for antibiotic resistance AND the DNA of interest

Front 540

What is the type of DNA sequence in which the sequence on 1 strand reads the same in the same direction on the complementary strand?

Back 540

palindromic sequence (this is where restriction endonucleases cleave yielding sticky ends)

Front 541

In cloning, restriction enzymes cleave DNA at _____ base pair palindromic sequences, allowing for ______ of a fragment into a plasmid.

Back 541

4-6; insertion

Front 542

In cloning, tissue mRNA produced from DNA inserted into a bacterial plasmid is isolated and exposed to which enzyme, forming a cDNA library?

Back 542

reverse transcriptase

Front 543

In cloning, tissue mRNA is isolated and exposed to reverse transcriptase, forming a _____library.

Back 543

cDNA = complementary DNA

Front 544

In cloning, _______ is isolated and exposed to reverse transcriptase, forming a cDNA library.

Back 544

mRNA

Front 545

Which type of enzymes cleave DNA at 4- to 6-bp palindromic sequences in cloning?

Back 545

restriction enzymes/endonucleases

Front 546

What distinguishes cDNA from most nuclear DNA?

Back 546

it lacks introns since it was produced from processed mRNA

Front 547

acute (adj.)

Back 547

sharp, severe

Front 548

In which laboratory technique do dideoxynucleotides halt DNA polymerization at each base, generating sequences of various lengths that encompass the entire original sequence so that the terminated fragments are electrophoresed and the original sequence can be deduced?

Back 548

Sanger DNA sequencing

Front 549

In Sanger DNA sequencing, dideoxynucleotides halt DNA polymerization at each base, generating sequences of various lengths. These terminated fragments then undergo which procedure?

Back 549

gel electrophoresis

Front 550

True or False: In Sanger DNA sequencing, electrophoresis of terminated fragments with subsequent sequencing of fragments allows revealing of the original DNA sequence.

Back 550

true

Front 551

What property of Sanger DNA sequencing is crucial to the ability to determine a DNA sequence using electrophoresis?

Back 551

A dideoxyribonucleotide must interrupt the sequence at every base in the sequence

Front 552

There are two transgenic strategies in mice: ______ insertion of a gene and _______ insertion or deletion of a gene.

Back 552

random/constitutive; targeted/conditional

Front 553

Targeted insertion or deletion of a gene into the genome of a mouse occurs through which step?

Back 553

homologous recombination with mouse gene

Front 554

How does an antibiotic-controlled promoter allow you to study genes in which the deletion of that particular gene leads to death of the embryo?

Back 554

The gene can be "turned off" following the embryo stage using the antibiotic

Front 555

_____ (Knock-out/Knock-in) refers to the removal of a gene from a host genome and _____ (knock-out/knock-in) refers to the insertion of a gene into a host genome.

Back 555

knock-out; knock-in

Front 556

In RNA inhibition, the degradation of target mRNA inhibits which process?

Back 556

translation; thus reducing gene expression

Front 557

True or False: Genes can be manipulated at specific developmental points using an inducible Cre-lox system with an antibiotic-controlled promoter.

Back 557

true

Front 558

In which laboratory technique do dideoxynucleotides halt DNA polymerization at each base, generating sequences of various lengths that encompass the entire original sequence so that the terminated fragments are electrophoresed and the original sequence can be deduced?

Back 558

Sanger DNA sequencing

Front 559

In Sanger DNA sequencing, dideoxynucleotides halt DNA polymerization at each base, generating sequences of various lengths. These terminated fragments then undergo which procedure?

Back 559

gel electrophoresis

Front 560

True or False: In Sanger DNA sequencing, electrophoresis of terminated fragments with subsequent sequencing of fragments allows revealing of the original DNA sequence.

Back 560

true

Front 561

What property of Sanger DNA sequencing is crucial to the ability to determine a DNA sequence using electrophoresis?

Back 561

A dideoxyribonucleotide must interrupt the sequence at every base in the sequence

Front 562

There are two transgenic strategies in mice: ______ insertion of a gene and _______ insertion or deletion of a gene.

Back 562

random/constitutive; targeted/conditional

Front 563

Targeted insertion or deletion of a gene into the genome of a mouse occurs through which step?

Back 563

homologous recombination with mouse gene

Front 564

How does an antibiotic-controlled promoter allow you to study genes in which the deletion of that particular gene leads to death of the embryo?

Back 564

The gene can be "turned off" following the embryo stage using the antibiotic

Front 565

_____ (Knock-out/Knock-in) refers to the removal of a gene from a host genome and _____ (knock-out/knock-in) refers to the insertion of a gene into a host genome.

Back 565

knock-out; knock-in

Front 566

In RNA inhibition, the degradation of target mRNA inhibits which process?

Back 566

translation; thus reducing gene expression

Front 567

True or False: Genes can be manipulated at specific developmental points using an inducible Cre-lox system with an antibiotic-controlled promoter.

Back 567

true

Front 568

Regarding model systems, genes can be manipulated at specific development points using an inducible Cre-lox system with what type of promoter?

Back 568

anitbiotic-controlled promoter

Front 569

What is the mechanism in which double-stranded RNA is synthesized complementary to the mRNA sequence of interest and transfected into human cells, where the dsRNA then separates and promotes degradation of the target mRNA knocking down gene expression?

Back 569

RNA inhibition

Front 570

In RNA inhibition, dsRNA is synthesized then transfected into human cells where it separates and promotes the degradation of which molecule?

Back 570

mRNA

Front 571

Regarding model systems, antibiotic-controlled promoters are used to manipulate gene expression at different _____ points in the growth of the mouse host.

Back 571

developmental -- so you can see the effects of the gene expression at various stages

Front 572

What phase of mitosis are the chromosomes in when performing a karyotype?

Back 572

metaphase-- where homologous pairs are aligned

Front 573

What process compares chromosomes based on morphology, size, arm-length ratio, and banding pattern?

Back 573

karyotyping

Front 574

What is the diagnostic value of a karyotype?

Back 574

It can diagnose chromosomal imbalances

Front 575

In a karyotype, chromosomes are paired and arranged in what pattern?

Back 575

They are arranged by chromosome number

Front 576

Name three types of chromosome imbalances that can be seen on a karyotype.

Back 576

Autosomal trisomies (aneuploides--monosomies can be seen too--if they were compatible with life), microdeletions, and sex chromosome disorders

Front 577

What tissue can be used to perform a karyotype on a fetus?

Back 577

placenta and amniotic fluid

Front 578

What are four tissues that can be used for chromosomal analysis?

Back 578

blood, bone marrow, amniotic fluid or placental tissue

Front 579

The _____ _____ of a genetic disease indicates that the nature and severity of the phenotype varies from one individual to another with the same disease.

Back 579

variable expression (e.g. patients with marfan's may have the same genotype but may have more or less severe phenotypic expression)

Front 580

If a genetic disease shows _____ _____, it means that not all individuals with the mutant genotype will show the complete mutant phenotype.

Back 580

incomplete penetrance

Front 581

A genetic disease that shows _____ has a different phenotype depending on whether the mutation is inherited from the mother or from the father.

Back 581

imprinting

Front 582

True or False: Linkage disequilibrium can be measured in families as well as in larger populations.

Back 582

False; linkage disequilibrium can be measured only in larger populations.

Front 583

What word describes the situation in which cells in the body have a different genetic makeup?

Back 583

mosaicism

Front 584

What is the name of the phenomenon whereby a genetic disease has an earlier onset or worsening severity in each subsequent generation?

Back 584

anticipation

Front 585

What word describes the phenomenon of a single gene having more than one effect on an individual's phenotype?

Back 585

pleitropy

Front 586

True or False: Prader-Willi syndrome is an example of genetic imprinting.

Back 586

true- it occurs when the gene is deleted from normally active Paternal allele, if the gene is deleted from the normally active Maternal allele, angelMan's syndrome with result

Front 587

True or False: Lyonization (ie, the random inactivation of one X chromosome in females) is an example of mosaicism.

Back 587

true

Front 588

A patient has inherited a mutation in a tumor suppressor gene. Mutation of the remaining (previously normal) copy of the tumor suppressor gene represents a loss of _____, which may lead to the development of cancer.

Back 588

Heterozygosity; the patient was previously a heterozygote for the lost tumor suppressor gene

Front 589

True or False: Oncogenes, in a manner similar to tumor-suppressor genes, must have a deletion/mutation in the complementary allele before cancer develops.

Back 589

False; the mutation of a single oncogene can produce cancer

Front 590

A genetic disease that shows _____ _____ will have mutations at different loci that produce the same phenotype.

Back 590

locus heterogeneity

Front 591

True or False: Angelman's syndrome is an example of genetic imprinting.

Back 591

true; if the gene is deleted from normally active Maternal allele, angelMan's syndrome with result, if deleted from normally active Paternal allele, Prader-Willi syndrome will result

Front 592

True or False: Albinism is an example of a genetic disease that demonstrates locus heterogeneity.

Back 592

true- more than one gene at more than one locus has been implicated in this phenotype

Front 593

Give an example of disease that shows genetic anticipation.

Back 593

Huntington's disease-- the severity of the disease is worse and/or age of onset is earlier in succeeding generations

Front 594

What term describes the presence of both normal and mutated mitochondrial DNA (mtDNA), resulting in variable expression in mitochondrial inherited diseases?

Back 594

heteroplasmy

Front 595

A nonfunctional altered protein that also prevents the normal gene product from functioning is called what?

Back 595

dominant negative mutation

Front 596

Name the genetic phenomenon that occurs when the offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent.

Back 596

uniparental disomy

Front 597

The tendency for certain alleles to be inherited together more often than is expected by chance is called what?

Back 597

linkage disequilibrium

Front 598

What equation describes the allele prevalence in a population that is in Hardy-Weinberg equilibrium?

Back 598

p + q = 1

Front 599

True or False: The Hardy-Weinberg law assumes that there are no mutations at the locus being studied.

Back 599

true

Front 600

What equation describes the disease prevalence in a population that is in Hardy-Weinberg equilibrium?

Back 600

p2 + 2pq + q2 = 1 where q2 is the prevalence of an autosomal recessive disease, and 2pq is the prevalence of heterozygosity or carriers in an autosomal recessive disease

Front 601

What is the heterozygote prevalence in a population that is in Hardy-Weinberg equilibrium?

Back 601

2pq

Front 602

True or False: The Hardy-Weinberg law assumes that there is no selection for any of the genotypes at the locus being studied.

Back 602

true- there must be no environmental advantage to having on genotype, or it would be selected for

Front 603

In Hardy-Weinberg population genetics, what do "p" and "q" represent?

Back 603

allele frequencies

Front 604

True or False: The Hardy-Weinberg law assumes that mating is completely random.

Back 604

true-- no incest either!

Front 605

True or False: The Hardy-Weinberg law assumes that there is no migration into or out of the population being considered.

Back 605

true

Front 606

True or False: The Hardy-Weinberg law shows that advantageous alleles are more frequently selected during mating and thus appear more frequently in the population.

Back 606

False; it assumes that there is no selection of one genotype over another and that mating is random

Front 607

True or False: The Hardy-Weinberg law shows that mutations can either be advantageous or disadvantageous or that they can have no effect on an organism's survival.

Back 607

False; it assumes that there are no mutations at the locus being studied

Front 608

The Hardy-Weinberg law shows that the prevalence of an X-linked recessive disease in males is represented by _____ (q/q2) and in females is represented by _____ (q/q2).

Back 608

q in males; q2 in females

Front 609

The prevalence of which type of genetic disease is indicated by males = q and females = q2 using Hardy-Weinberg genetics?

Back 609

x-linked recessive diseases

Front 610

How is Prader-Willi syndrome inherited?

Back 610

loss/deactivation of normally active Paternal allele on chromosome 15

Front 611

In genetics, what does the term imprinting refer to?

Back 611

the deletion of an active allele leads to disease because only one allele is active at the locus (due to methylation of the imprinted or inactive allele) -- this means that a different phenotype can result depending on whether there is deletion of maternal or paternal allele

Front 612

How is Angelman's syndrome inherited?

Back 612

It is inherited via the deactivation of normally active maternal allele on chromosome 15

Front 613

In genetics, how is an imprinted disease inherited?

Back 613

A disease in which imprinting plays a role is inherited in an autosomal fashion, but the disease can vary depending on whether the paternal or maternal allele is affected

Front 614

Where is the gene located in Prader-Willi syndrome? In Angelman's syndrome?

Back 614

Both syndromes are due to inactivation or deletion of genes on chromosome 15

Front 615

What are the signs of Prader-Willi syndrome?

Back 615

hyperphagia, obesity, hypotonia, hypogonadism, and mental retardation

Front 616

What are the signs of Angelman's syndrome?

Back 616

"happy puppet syndrome", mental retardation, seizures, inappropriate laughter, ataxia

Front 617

Angelman's syndrome and Prader-Willi syndrome are examples of what kind of genetic inheritance?

Back 617

imprinting

Front 618

True or False: Imprinting can also occur as a result of uniparental disomy.

Back 618

true

Front 619

In Leber's hereditary optic neuropathy, vision loss is _____ (central/peripheral).

Back 619

central

Front 620

Autosomal-dominant patterns of inheritance are often found in diseases caused by defects in _____ genes.

Back 620

structural

Front 621

True or False: A mother with an X-linked dominant disease may pass the disease only to her daughters.

Back 621

False; both her sons and her daughters may be affected (50% of passing along the allele to either her sons or daughters)

Front 622

True or False: Patients with autosomal-dominant disorders often present clinically after puberty.

Back 622

true

Front 623

What is the pattern of inheritance of hypophosphatemic rickets?

Back 623

x-linked dominant

Front 624

What is the mode of inheritance if a disease is present in many generations and affects both males and females in roughly equal proportions?

Back 624

autosomal dominant

Front 625

What is the mode of inheritance in a family in which a disease is transmitted only through the mother and all children (both boys and girls) are affected?

Back 625

mitochondrial inheritance

Front 626

Autosomal-recessive patterns of inheritance are often found in diseases caused by defects in _____.

Back 626

enzymes

Front 627

True or False: A mother may pass a disease with a mitochondrial pattern of inheritance to both her sons and her daughters.

Back 627

true since all mitochondrial DNA is passed through the mother

Front 628

What is the mode of inheritance if a gene is present in a single generation and 25% of the offspring from the same two parents have the disease?

Back 628

autosomal recessive

Front 629

What is the pattern of inheritance of Leber's hereditary optic neuropathy?

Back 629

mitochondrial inheritance

Front 630

True or False: Patients with autosomal-recessive disorders often present clinically during childhood.

Back 630

true because autosomal recessive diseases are often more severe than autosomal dominant ones

Front 631

What is the pattern of inheritance of mitochondrial myopathies?

Back 631

mitochondrial

Front 632

What would you expect to see on urinalysis in a patient with hypophosphatemic rickets?

Back 632

You would expect an increased urine phosphate level since there is proximal tubule phosphate loss

Front 633

Variable expression of mitochondrial inheritance in a population is due to _____ (heteroplasmy/uniparental disomy).

Back 633

heteroplasmy

Front 634

True or False: Hypophosphatemic rickets can be treated by vitamin D supplementation.

Back 634

false; it is caused excess secretion of phosphate, not deficiency of vitamin D-- hence this disease is also called vitamin D resistant rickets

Front 635

What is the mechanism of phosphate wasting in hypophosphatemic rickets?

Back 635

There is increased phosphate wasting at the proximal renal tubule

Front 636

Which cells are affected in Leber's hereditary optic neuropathy?

Back 636

the degeneration of retinal ganglion cells and their axons

Front 637

In general, are autosomal-dominant or autosomal-recessive disorders more severe?

Back 637

autosomal recessive

Front 638

True or False: A patient who has had a progressive loss of visual acuity with a positive family history has a good probability of having Leber's hereditary optic neuropathy.

Back 638

False; the vision loss in Leber's hereditary optic neuropathy is acute

Front 639

What is the mode of inheritance in a family in which 50% of sons are affected and there is no male-to-male transmission?

Back 639

x-linked recessive

Front 640

What percentage of sons of a carrier mother are expected to inherit an X-linked recessive disease?

Back 640

50%

Front 641

True or False: Females are never affected by X-linked recessive diseases.

Back 641

False; heterozygous females may be affected by some X-linked recessive diseases

Front 642

True or False: X-linked recessive diseases are commonly more severe in males than in females.

Back 642

true

Front 643

Are X-linked dominant diseases transmitted through the mother only, through the father only, or through both parents?

Back 643

both parents

Front 644

True or False: A mother with an X-linked dominant disease may pass the disease to either her sons or her daughters.

Back 644

true

Front 645

True or False: A father with an X-linked dominant disease will pass the disease to all of his daughters but none of his sons.

Back 645

true

Front 646

What is the mode of inheritance of achondroplasia?

Back 646

autosomal dominant

Front 647

A mother with achondroplasia is pregnant; what is the likelihood that her child will also have the disease?

Back 647

50%

Front 648

Achondroplasia is the result of a defect in the ____ receptor.

Back 648

fibroblast growth factor receptor 3 (FGF3)

Front 649

A patient has dwarfism with short limbs but a normally sized head and trunk. What is the most likely diagnosis?

Back 649

achondroplasia

Front 650

What is the paternal age more likely to pass on the trait for achondroplasia: 20, 30, or 40?

Back 650

40 achondroplasia is associated with advanced paternal age

Front 651

True or False: Achondroplasia results from a defect in cell signaling.

Back 651

True; there is no signaling from the missing fibroblast growth factor 3 receptor

Front 652

What is the mode of inheritance of adult polycystic kidney disease?

Back 652

autosomal dominant

Front 653

True or False: Adult polycystic kidney disease is associated with mitral valve prolapse.

Back 653

true

Front 654

A patient with known APKD undergoes a right renal biopsy in the hospital that shows multiple large cysts; what would a biopsy of the left kidney show?

Back 654

It would also demonstrate the large cysts typical of APKD; this disease is always bilateral

Front 655

A patient has hematuria, hypertension, and progressive renal failure. His kidneys are both massively dilated as a result of multiple large cysts. What is the most likely diagnosis?

Back 655

ADPKD

Front 656

True or False: Adult polycystic kidney disease is associated with primary adrenocortical insufficiency.

Back 656

False; but is associated with polycystic liver disease, berry aneurysm, and mitral valve prolapse

Front 657

Ninety percent of cases of adult polycystic kidney disease are associated with a mutation in what gene?

Back 657

APKD1

Front 658

How many parents must carry the gene that causes the infantile form of polycystic kidney disease?

Back 658

Both parents must carry the gene to pass the trait on to the child since this disease is autosomal recessive

Front 659

The gene APKD1 is located on which chromosome?

Back 659

Chromosome 16 (remember: 16 letters in 7 "polycystic kidney")

Front 660

Adult polycystic kidney disease is inherited in an autosomal-_____ (dominant/recessive) pattern, whereas juvenile polycystic kidney disease is associated with an autosomal-_____ (dominant/recessive) pattern.

Back 660

dominant; recessive

Front 661

True or False: Adult polycystic kidney disease is associated with dilated cardiomyopathy.

Back 661

False; but is associated with polycystic liver disease, berry aneurysm, and mitral valve prolapse

Front 662

True or False: Adult polycystic kidney disease is associated with berry aneurysms.

Back 662

true

Front 663

What is the mode of inheritance of familial adenomatous polyposis?

Back 663

autosomal dominant

Front 664

A patient has adenomatous polyps that carpet his colon. What is the most likely diagnosis?

Back 664

familial adenomatous polyposis

Front 665

True or False: A patient with familial adenomatous polyposis has no increased risk of cancer.

Back 665

False; adenomatous polyps will progress to cancer unless they are resected

Front 666

Achondroplasia is the result of a defect in the ____ receptor.

Back 666

fibroblast growth factor receptor 3 (FGF3)

Front 667

The defect that leads to familial adenomatous polyposis is found on chromosome ____.

Back 667

5 (remember: 5 letters in "polyp")

Front 668

A patient has dwarfism with short limbs but a normally sized head and trunk. What is the most likely diagnosis?

Back 668

achondroplasia

Front 669

The defect that leads to familial adenomatous polyposis is found in the ____ gene.

Back 669

APC (A Polypy Colon or A Polyp Carpet)

Front 670

What is the paternal age more likely to pass on the trait for achondroplasia: 20, 30, or 40?

Back 670

40 achondroplasia is associated with advanced paternal age

Front 671

True or False: Achondroplasia results from a defect in cell signaling.

Back 671

True; there is no signaling from the missing fibroblast growth factor 3 receptor

Front 672

What is the mode of inheritance of adult polycystic kidney disease?

Back 672

autosomal dominant

Front 673

True or False: Adult polycystic kidney disease is associated with mitral valve prolapse.

Back 673

true

Front 674

A patient with known APKD undergoes a right renal biopsy in the hospital that shows multiple large cysts; what would a biopsy of the left kidney show?

Back 674

It would also demonstrate the large cysts typical of APKD; this disease is always bilateral

Front 675

A patient has hematuria, hypertension, and progressive renal failure. His kidneys are both massively dilated as a result of multiple large cysts. What is the most likely diagnosis?

Back 675

ADPKD

Front 676

True or False: Adult polycystic kidney disease is associated with primary adrenocortical insufficiency.

Back 676

False; but is associated with polycystic liver disease, berry aneurysm, and mitral valve prolapse

Front 677

Ninety percent of cases of adult polycystic kidney disease are associated with a mutation in what gene?

Back 677

APKD1

Front 678

A patient has dwarfism with short limbs but a normally sized head and trunk. What is the most likely diagnosis?

Back 678

achondroplasia

Front 679

What is the paternal age more likely to pass on the trait for achondroplasia: 20, 30, or 40?

Back 679

40; achondroplasia is associated with advanced paternal age

Front 680

True or False: Achondroplasia results from a defect in cell signaling.

Back 680

True; there is no signaling from the missing fibroblast growth factor 3 receptor

Front 681

What is the mode of inheritance of adult polycystic kidney disease?

Back 681

autosomal dominant

Front 682

True or False: Adult polycystic kidney disease is associated with mitral valve prolapse.

Back 682

true

Front 683

A patient with known APKD undergoes a right renal biopsy in the hospital that shows multiple large cysts; what would a biopsy of the left kidney show?

Back 683

It would also demonstrate the large cysts typical of APKD; this disease is ALWAYS BILATERAL

Front 684

A patient has hematuria, hypertension, and progressive renal failure. His kidneys are both massively dilated as a result of multiple large cysts. What is the most likely diagnosis?

Back 684

ADPKD

Front 685

True or False: Adult polycystic kidney disease is associated with primary adrenocortical insufficiency.

Back 685

False; but is associated with polycystic liver disease, berry aneurysm, and mitral valve prolapse

Front 686

Ninety percent of cases of adult polycystic kidney disease are associated with a mutation in what gene?

Back 686

APKD1 (adult polycystic kidney disease)

Front 687

How many parents must carry the gene that causes the infantile form of polycystic kidney disease?

Back 687

Both parents must carry the gene to pass the trait on to the child since this disease is autosomal recessive

Front 688

The gene APKD1 is located on which chromosome?

Back 688

Chromosome 16 (remember: 16 letters in "polycystic kidney")

Front 689

Adult polycystic kidney disease is inherited in an autosomal-_____ (dominant/recessive) pattern, whereas juvenile polycystic kidney disease is associated with an autosomal-_____ (dominant/recessive) pattern.

Back 689

dominant; recessive

Front 690

True or False: Adult polycystic kidney disease is associated with dilated cardiomyopathy.

Back 690

False; but is associated with polycystic liver disease, berry aneurysm, and mitral valve prolapse

Front 691

True or False: Adult polycystic kidney disease is associated with berry aneurysms.

Back 691

true

Front 692

What is the mode of inheritance of familial adenomatous polyposis?

Back 692

autosomal dominant

Front 693

A patient has adenomatous polyps that carpet his colon. What is the most likely diagnosis?

Back 693

familial adenomatous polyposis

Front 694

True or False: A patient with familial adenomatous polyposis has no increased risk of cancer.

Back 694

False; adenomatous polyps will 100% of the time progress to cancer unless they are resected

Front 695

The defect that leads to familial adenomatous polyposis is found on chromosome ____.

Back 695

5 (remember: 5 letters in "polyp")

Front 696

The defect that leads to familial adenomatous polyposis is found in the ____ gene.

Back 696

APC (A Polypy Colon, A Polyp Carpet)

Front 697

A patient with FAP asks you if he might not eventually develop colon cancer; what is your reply?

Back 697

Patients with FAP will all progress to colon cancer unless the colon is resected

Front 698

What is the mode of inheritance of familial hypercholesterolemia?

Back 698

autosomal dominant

Front 699

Familial hypercholesterolemia is the result of a defect in what type of receptor?

Back 699

LDL receptor

Front 700

In patients with familial hypercholesterolemia, heterozygotes can be expected to have a cholesterol level around ____ mg/dL, and homozygotes can be expected to have a cholesterol level around ____ mg/dL.

Back 700

300; 700

Front 701

A middle-aged woman had a myocardial infarction 20 years ago, and has tendon xanthomas on her Achilles tendon. What is the most likely diagnosis?

Back 701

familial hypercholesterolemia

Front 702

A child is born to a parent homozygous for Osler-Weber-Rendu syndrome; what are the odds that the child will also have the disease?

Back 702

100%; this is an autosomal dominant disease

Front 703

What is another name for Osler-Weber-Rendu syndrome?

Back 703

Hereditary hemorrhagic telangiectasia

Front 704

What is the tissue involved in Osler-Weber-Rendu syndrome?

Back 704

this is a disorder of the blood vessels

Front 705

Why is recurrent epistaxis a common finding in Osler-Weber-Rendu syndrome?

Back 705

Malformed blood vessels in the nose can break and cause frequent nosebleeds

Front 706

A patient has multiple telangiectasias, skin discolorations, and notes recurrent epistaxis; what other physical finding might be expected?

Back 706

arteriovenous malformations (AVMs)- this is the constellation of symptoms/findings seen with hereditary hemorrhagic telangectasia/ Osler Weber Rendu

Front 707

What is the mode of inheritance of hereditary spherocytosis?

Back 707

autosomal dominant

Front 708

A patient has hemolytic anemia, increased mean corpuscular hemoglobin concentration, and spheroid erythrocytes. What is the most likely diagnosis?

Back 708

hereditary spherocytosis

Front 709

True or False: RBCs in patients with hereditary spherocytosis have increased concentrations of hemoglobin.

Back 709

true (inc MCHC) red blood cells have less surface area and volume and hence more concentrated hemoglobin

Front 710

True or False: Hereditary spherocytosis is associated with abnormally shaped RBCs.

Back 710

True; instead of a biconcave disk, RBCs are shaped like spheres

Front 711

A patient with known hereditary spherocytosis comes in complaining of fatigue, shortness of breath, and feels pale; what is a possible diagnosis and its mechanism?

Back 711

This patient appears to be anemic, likely due to increased hemolysis of spheroid erythrocytes

Front 712

In refractory cases, how can you cure hereditary spherocytosis?

Back 712

splenectomy- the spleen is removing the malformed RBCs

Front 713

What is the mode of inheritance of Huntington's disease?

Back 713

autosomal dominant

Front 714

A patient develops depression, progressive dementia, and choreiform movements. What is the most likely diagnosis, and how old are they likely to be?

Back 714

Huntington's disease; symptoms usually begin between 20 and 50 years of age

Front 715

You are performing an autopsy on a man who had Huntington's disease; what would you find on inspection of the brain?

Back 715

Huntington's disease is associated with atrophy of the caudate leading to "bat wing ventricles"

Front 716

Which psychiatric diagnoses are commonly associated with Huntington's disease?

Back 716

depression and progressive dementia

Front 717

Huntington's disease is associated with _____ movements.

Back 717

choreiform -- thus it can also be called Huntington's chorea (purposeless, dancelike movements)

Front 718

True or False: Symptoms of Huntington's disease generally manifest between the ages of 20 and 50 years.

Back 718

true

Front 719

The defect that leads to Huntington's disease is found on chromosome ____.

Back 719

4; (remember: Hunting 4 food)

Front 720

What would a genetic analysis of a patient with Huntington's disease demonstrate on chromosome 4?

Back 720

Trinucleotide repeats of (CAG)n in the Huntington gene

Front 721

Patients with Huntington's disease have decreased levels of what in their central nervous system?

Back 721

γ-aminobutyric acid (GABA) and acetylcholine (ACh)

Front 722

True or False: Patients with Huntington's disease have increased levels of γ-aminobutyric acid and acetylcholine in the central nervous system.

Back 722

False; Huntington's disease is associated with decreased levels of these substances

Front 723

True or False: Symptoms of Huntington's disease generally manifest between the ages 10 and 20 years, before most people have had children.

Back 723

False; symptoms of Huntington's disease manifest between the ages of 20 and 50 years

Front 724

What is the mode of inheritance of Marfan's syndrome?

Back 724

autosomal dominant

Front 725

Marfan's syndrome is the result of a mutation in the _____ gene that leads to connective tissue disorders.

Back 725

fibrillin

Front 726

True or False: Marfan's syndrome is associated with a tall habitus and long, tapering fingers and toes.

Back 726

true

Front 727

True or False: Marfan's syndrome is associated with arachnodactyly.

Back 727

True; arachnodactyly describes long, tapering fingers and toes

Front 728

True or False: Marfan's syndrome is associated with hyperflexible joints.

Back 728

true- as is Ehler's danlos- an inherited collagen defect

Front 729

True or False: Marfan's syndrome is associated with cystic medial necrosis of the aorta.

Back 729

true- this can lead to aortic incompetence and dissecting aortic aneurysms

Front 730

True or False: Marfan's syndrome is associated with aortic incompetence.

Back 730

true- because of cystic medial necrosis of the aorta

Front 731

True or False: Marfan's syndrome is associated with dissecting aortic aneurysms.

Back 731

true- because of cystic medial necrosis of the aorta

Front 732

True or False: Marfan's syndrome is associated with subluxation of the lenses.

Back 732

true

Front 733

True or False: Marfan's syndrome is associated with skeletal abnormalities such as arachnodactyly and hyperflexible joints but no abnormalities of the cardiovascular system.

Back 733

False; patients with Marfan's syndrome can have cystic medial necrosis of the aorta leading to aortic insufficiency and dissecting aortic aneurysms
they also have floppy mitral valves

Front 734

A patient with Marfan's asks you whether, given his elastic joint flexibility, this disorder is from a mutation in the elastin gene. How do you reply?

Back 734

The disorder is actually a mutation in the fibrillin gene, which in turn affects the organization of elastin in various tissues

Front 735

What is the inheritance pattern of multiple endocrine neoplasias?

Back 735

autosomal dominant

Front 736

How many different syndromes are considered "multiple endocrine neoplasias"?

Back 736

Three, collectively known as MEN I, MEN II, and MEN III (or MEN I, and MEN2A and MEN2B)

Front 737

True or False: MEN syndromes may involve cancers originating in the adrenal cortex?

Back 737

False; MEN syndromes cause familial tumors of endocrine glands, and include cancers in the adrenal medulla but not the adrenal cortex

Front 738

Name 5 endocrine organs that develop tumors in the multiple endocrine neoplasia syndromes

Back 738

pancreas, pituitary, parathyroid, adrenal medulla, and thyroid

Front 739

True or False: MEN I is associated with a mutation in the ret gene.

Back 739

False; MEN II/MEN2A and MEN III/MEN2B are associated with ret mutations

Front 740

A tall male patient enters the ED with the combination of a dissecting ascending aorta and acute mitral valve prolapse; what disorder might explain these findings?

Back 740

marfan's syndrome- associated with cystic medial necrosis of the aorta which may lead to a dissection, as well as a floppy mitral valve prone to prolapse

Front 741

What is the mode of inheritance of neurofibromatosis type 1?

Back 741

autosomal dominant- this is also called von Recklinghausen's disease

Front 742

What is the mode of inheritance of von Recklinghausen's disease?

Back 742

autosomal dominant- this is also called NF1

Front 743

What is another name for neurofibromatosis type 1?

Back 743

von Recklinghausen's disease

Front 744

Which chromosome would you want to study if a patient comes in with signs and symptoms suggestive of von Recklinghausen's disease?

Back 744

The defect is a mutation on the long arm of chromosome 17 (remember: there are 17 letters in "von Recklinghausen")

Front 745

A patient has café-au-lait spots, Lisch nodules, scoliosis, neural tumors, and pheochromocytoma. What is the most likely diagnosis?

Back 745

Neurofibromatosis type 1 (von Recklinghausen's disease)

Front 746

True or False: Neurofibromatosis type 1 is associated with café-au-lait spots.

Back 746

true

Front 747

True or False: Neurofibromatosis type 1 is associated with neural tumors.

Back 747

true

Front 748

True or False: Neurofibromatosis type 1 is associated with Lisch nodules.

Back 748

true

Front 749

What is another term for the pigmented iris hamartomas associated with neurofibromatosis?

Back 749

lisch nodules

Front 750

True or False: Neurofibromatosis type 1 is associated with skeletal disorders such as scoliosis.

Back 750

true

Front 751

True or False: Neurofibromatosis type 1 is associated with pheochromocytoma.

Back 751

true

Front 752

True or False: Neurofibromatosis type 1 is associated with ash leaf spots.

Back 752

False; it is associated with café-au-lait spots (tuberous sclerosis is associated with "ash leaf spots")

Front 753

True or False: Neurofibromatosis type 1 is associated with skin and eye abnormalities but no skeletal abnormalities.

Back 753

False; neurofibromatosis type 1 may be associated with skeletal abnormalities such as scoliosis

Front 754

True or False: Neurofibromatosis is not associated with any increased risk of cancer.

Back 754

False; neurofibromatosis type 1 is associated with neural tumors, optic pathway gliomas, pheochromocytoma, and increased tumor susceptibility

Front 755

What is the mode of inheritance for neurofibromatosis type 2?

Back 755

autosomal dominant

Front 756

A patient has bilateral acoustic neuroma, optic pathway gliomas, and juvenile cataracts. What is the most likely diagnosis?

Back 756

neurofibromatosis type 2 (NF2)

Front 757

A patient presents with bilateral acoustic neuromas; her underlying disease is most likely _____ (neurofibromatosis type 1/neurofibromatosis type 2)?

Back 757

Neurofibromatosis type 2 is commonly associated with bilateral acoustic neuromas

Front 758

True or False: Neurofibromatosis type 2 is associated with juvenile cataracts.

Back 758

true

Front 759

True or False: Neurofibromatosis type 2 is associated with skin findings that are similar to those of neurofibromatosis type 1.

Back 759

False; neurofibromatosis type 2 is not associated with abnormal skin findings

Front 760

True or False: Neurofibromatosis type 2 is not associated with tumors.

Back 760

False; neurofibromatosis type 2 is associated with bilateral acoustic neuromas

Front 761

Neurofibromatosis type 2 is a result of a mutation in the gene _____ found on chromosome _____.

Back 761

NF2, 22

Front 762

What is the mode of inheritance of tuberous sclerosis?

Back 762

autosomal dominant

Front 763

A patient has adenoma sebaceum on his face, ash leaf spots on his trunk, mental retardation, and seizures. What the most likely diagnosis?

Back 763

Tuberous sclerosis

Front 764

Where would you find adenoma sebaceum lesions on a patient with tuberous sclerosis?

Back 764

These lesions are hamartomatous angiofibromas that are found on the face

Front 765

True or False: Tuberous sclerosis is associated with cortical and retinal hamartomas.

Back 765

true

Front 766

What renal findings might distinguish a patient with tuberous sclerosis from a patient with APKD?

Back 766

While both will have renal cysts, tuberous sclerosis is associated with renal angiomyolipomas

Front 767

What is a cardiac manifestation of tuberous sclerosis?

Back 767

Cardiac rhabdomyoma

Front 768

True or False: Tuberous sclerosis is not associated with any abnormal skin findings.

Back 768

False; tuberous sclerosis is associated with ash leaf spots and adenoma sebaceum

Front 769

True or False: Patients with tuberous sclerosis have no central nervous system involvement.

Back 769

False; tuberous sclerosis is associated with mental retardation and seizures

Front 770

Compared to the general population, patients with tuberous sclerosis have an increased incidence of which brain tumor?

Back 770

astrocytomas

Front 771

True or False: All patients who inherit the gene in tuberous sclerosis will display very similar signs and symptoms.

Back 771

False; although autosomal dominant, this disease has incomplete penetrance and a variable presentation

Front 772

What is the mode of inheritance of von Hippel-Lindau disease?

Back 772

autosomal dominant

Front 773

A patient has hemangiomas of the retina and cerebellum, as well as bilateral renal cell carcinoma. What is the most likely diagnosis?

Back 773

von Hippel Lindau disease

Front 774

True or False: An individual with von Hippel-Lindau disease may develop benign vascular tumors in the retina.

Back 774

true; this describes retinal hemangiomas

Front 775

A patient has hematuria and flank pain; further work-up shows multiple bilateral renal cell carcinomas and makes you suspect which disease?

Back 775

von hippel lindau disease: About half of the individuals with von Hippel-Lindau disease will develop multiple bilateral renal cell carcinomas

Front 776

True or False: Von Hippel-Lindau disease is associated with pheochromocytomas.

Back 776

False; Von Hippel-Lindau disease is associated with bilateral renal cell carcinoma

Front 777

True or False: Von Hippel-Lindau disease is associated with acoustic neuromas.

Back 777

False; von Hippel-Lindaudisease is associated with hemangioblastomas of the retina, the cerebellum, and the medulla

Front 778

True or False: Patients with von Hippel-Lindau disease do not have an increased risk of cancer.

Back 778

False; von Hippel-Lindau disease is associated with an increased risk of cancer

Front 779

Von Hippel-Lindau disease is a result of the deletion of the _____ gene, which functions as a _____ (tumor suppressor/oncogene).

Back 779

VHL; tumor suppressor

Front 780

The defect that leads to von Hippel-Lindau disease is found on chromosome _____.

Back 780

3 (remember: Von Hippel-Lindau = 3 words for chromosome 3)

Front 781

What is the mode of inheritance of cystic fibrosis?

Back 781

autosomal recessive

Front 782

What is the mode of inheritance of albinism?

Back 782

autosomal recessive

Front 783

What is the mode of inheritance of α1 antitrypsin deficiency?

Back 783

autosomal recessive

Front 784

What is the mode of inheritance of phenylketonuria?

Back 784

autosomal recessive

Front 785

What is the mode of inheritance of the thalassemias?

Back 785

autosomal recessive

Front 786

What is the mode of inheritance of sickle cell disease?

Back 786

autosomal recessive

Front 787

What is the mode of inheritance of the glycogen storage diseases?

Back 787

autosomal recessive

Front 788

What is the mode of inheritance of most mucopolysaccharidoses?

Back 788

autosomal recessive (Hunter's syndrome is x-linked recessive)

Front 789

Most mucopolysaccharidoses are inherited in a(n) _____-_____ pattern, except for _____ _____.

Back 789

autosomal recessive; hunter's syndrome

Front 790

Most sphingolipidoses are inherited in a(n) _____-_____ pattern, except for _____ _____.

Back 790

autosomal recessive; Fabry's disease

Front 791

What is the mode of inheritance of ARPKD?

Back 791

Autosomal recessive; this was formerly known as infantile polycystic kidney disease

Front 792

What is the mode of inheritance of hemochromatosis?

Back 792

autosomal recessive

Front 793

What is the pattern of inheritance of cystic fibrosis?

Back 793

autosomal recessive

Front 794

Cystic fibrosis results from a defect in which gene?

Back 794

CFTR

Front 795

Cystic fibrosis is caused by a defect on chromosome ____.

Back 795

7

Front 796

Cystic fibrosis is the result of a defective channel for what ion?

Back 796

Chloride (Cl-)

Front 797

Patients with cystic fibrosis characteristically have mucus plugs that disturb the function of which three organs?

Back 797

lungs, pancreas, and liver

Front 798

Which two pathogens are the most likely to cause recurrent pulmonary infections in a patient with cystic fibrosis?

Back 798

pseudomonas and staph aureus

Front 799

True or False: Recurrent lung infection, emphysema, and bronchiectasis are characteristic lung manifestations in patients with cystic fibrosis.

Back 799

False; patients with cystic fibrosis tend to have chronic bronchitis rather than emphysema

Front 800

What is the mechanism of pancreatic insufficiency in cystic fibrosis patients?

Back 800

Production of thick mucus forms plugs which block the pancreatic ducts

Front 801

An infant with failure to thrive also had meconium ileus as a newborn. What is the most likely diagnosis?

Back 801

cystic fibrosis

Front 802

High concentrations of chloride ions in the sweat are diagnostic for what disease?

Back 802

cystic fibrosis

Front 803

A patient is in the hospital for recurrent pulmonary infection with Pseudomonas. She has a history of steatorrhea and had a meconium ileus as an infant. What is the likely diagnosis?

Back 803

cystic fibrosis

Front 804

A male patient with cystic fibrosis asks you whether he will be able to have children; what is your response?

Back 804

Unfortunately, males with cystic fibrosis are infertile due to bilateral absence of the vas deferens

Front 805

Are patients with cystic fibrosis at risk for deficiencies of water-soluble vitamins or fat-soluble vitamins?

Back 805

fat soluble vitamins

Front 806

A patient with cystic fibrosis is at increased risk for the deficiency of what four vitamins?

Back 806

D, A, K, E all of which are fat soluble

Front 807

What is the most common lethal genetic disease among Caucasians?

Back 807

cystic fibrosis

Front 808

Treatment with what drug helps to loosen mucous plugs in patients with cystic fibrosis?

Back 808

n-acetylcysteine (mucomist)

Front 809

How does N-acetylcysteine free up mucous plugs?

Back 809

It cleaves the disulfide bonds that connect mucous glycoproteins

Front 810

In cystic fibrosis, the CFTR channel _____ (actively/passively) secretes chloride in the lungs and gastrointestinal tract and _____ (actively/passively) reabsorbs chloride from sweat.

Back 810

actively; actively

Front 811

What is the pattern of inheritance of fragile X syndrome?

Back 811

X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Fragile X)

Front 812

What is the pattern of inheritance of Duchenne's muscular dystrophy?

Back 812

X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Duchene)

Front 813

What is the pattern of inheritance of hemophilia A?

Back 813

X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Hemophilia A)

Front 814

What is the pattern of inheritance of hemophilia B?

Back 814

X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Hemophilia B)

Front 815

What is the pattern of inheritance of Fabry's disease?

Back 815

X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Fabry's)

Front 816

What is the pattern of inheritance of glucose-6-phosphate dehydrogenase deficiency?

Back 816

X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Glucose-6-phosphate dehydrogenase)

Front 817

What is the pattern of inheritance of Hunter's syndrome?

Back 817

X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Hunter's)

Front 818

What is the pattern of inheritance of ocular albinism?

Back 818

X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Ocular albinism)

Front 819

What is the pattern of inheritance of Lesch-Nyhan syndrome?

Back 819

X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Lesch-Nyhan)

Front 820

What is the pattern of inheritance of Bruton's agammaglobulinemia?

Back 820

X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Bruton's agammaglobulinemia)

Front 821

What is the pattern of inheritance of Wiskott-Aldrich syndrome?

Back 821

X-linked recessive (remember: Be Wise, Fool's GOLD Heeds False Hope; Wiskott-Aldrich)

Front 822

True or False: Glucose-6-phosphate dehydrogenase deficiency has the same pattern of inheritance as sickle cell anemia.

Back 822

False; glucose-6-phosphate dehydrogenase deficiency has X-linked recessive inheritance, whereas sickle cell anemia involves autosomal-recessive inheritance

Front 823

True or False:: Hunter's syndrome has the same pattern of inheritance as Fabry's disease.

Back 823

True; both have an X-linked recessive inheritance pattern

Front 824

True or False: Hunter's syndrome has the same pattern of inheritance as Hurler's syndrome.

Back 824

False; Hunter's syndrome has X-linked recessive inheritance, whereas Hurler's syndrome has autosomal-recessive inheritance

Front 825

True or False: Female carriers of X-linked recessive disorders are commonly affected by the disorders that they are carrying.

Back 825

False; they are rarely affected because of random inactivation of X chromosomes in each cell

Front 826

Why are female carriers of X-linked recessive disorders rarely affected?

Back 826

There is random inactivation of X chromosomes in each cell, a process known as lyonization

Front 827

Duchenne's muscular dystrophy is caused by a deletion of what gene?

Back 827

The dystrophin gene (remember: Duchenne's = Deleted Dystrophin)

Front 828

Is the loss of the dystrophin gene in Duchenne's muscular dystrophy the result of frame-shift mutation, unbalanced chromosomal translocation, or improper protein folding?

Back 828

Frame-shift mutation

Front 829

True or False: Patients with Duchenne's muscular dystrophy have accelerated muscle breakdown.

Back 829

true

Front 830

True or False: Patients with Duchenne's muscular dystrophy tend to present before the age of 5 years with muscle weakness.

Back 830

true

Front 831

In what muscle group does weakness normally begin in patients with Duchenne's muscular dystrophy?

Back 831

pelvic girdle muscles

Front 832

True or False: A classic presentation of Duchenne's muscular dystrophy is pelvic girdle weakness that progresses inferiorly.

Back 832

False; the weakness tends to first progress superiorly

Front 833

A 4-year-old boy needs to use his upper extremities to push against his legs in order to stand up. What is the name of this maneuver?

Back 833

gower's manuever- the action is necessary due to the weakness of the proximal muscles

Front 834

Gower's maneuver is associated with what disease?

Back 834

Duchenne's muscular dystrophy

Front 835

A 4-year-old boy with Duchenne's muscular dystrophy has hypertrophied calf muscles; what is the expected strength in his legs?

Back 835

This is actually pseudohypertrophy due to fibrofatty replacement of the muscle and you would expect muscle weakness

Front 836

True or False: Duchenne's muscular dystrophy is associated with cardiac myopathy.

Back 836

true

Front 837

True or False: Gower's maneuver indicates proximal lower limb weakness.

Back 837

true

Front 838

What aspect of the dystrophin gene makes it particularly susceptible to mutation?

Back 838

The dystrophin gene (DMD) is the largest known human gene, which allows a high rate of spontaneous mutations

Front 839

What is the role of dystrophin in the muscle?

Back 839

Dystrophin helps to anchor muscle fibers

Front 840

What two tissues rely most on the anchoring function of dystrophin?

Back 840

Skeletal and cardiac muscle

Front 841

Is Becker's muscular dystrophy more or less severe than Duchenne's muscular dystrophy?

Back 841

Becker's muscular dystrophy is less severe and presents later in life

Front 842

Muscular dystrophies can be diagnosed with the biopsy of _____ _____ and elevated _____ _____ levels in serum.

Back 842

skeletal muscle; creatine phosphokinase (CPK)

Front 843

Fragile X syndrome is caused by a defect in which gene?

Back 843

FMR1

Front 844

A defect in the FMR1 gene leads to what disease?

Back 844

fragile x syndrome

Front 845

What is the pattern of inheritance of fragile X syndrome?

Back 845

x-linked recessive

Front 846

True or False: Fragile X syndrome is caused by abnormal methylation of the FMR1 gene that alters its expression.

Back 846

true

Front 847

What is the most common genetic cause of mental retardation?

Back 847

down syndrome

Front 848

What is the second most common genetic cause of mental retardation?

Back 848

fragile x syndrome

Front 849

A male patient has a long face, a large jaw, large ears, autism, and macroorchidism. What is the most likely diagnosis?

Back 849

fragile x syndrome (remember: Fragile X = eXtra large testes, jaw, ears)

Front 850

True or False: Fragile X syndrome is associated with atrophic testes.

Back 850

False; fragile X syndrome is associated with macroorchidism

Front 851

What triplet is expanded in fragile X syndrome?

Back 851

CGG - Chromosomes Get Gouged

Front 852

True or False: Fragile X syndrome is associated with chromosomal breakage.

Back 852

true

Front 853

True or False: Huntington's disease is considered a trinucleotide expansion disease.

Back 853

True (remember: Try (trinucleotide) hunting for my fried eggs [X])

Front 854

Name four trinucleotide repeat disorders?

Back 854

Huntington's disease, myotonic dystrophy, friedrich's ataxia and fragile X syndrome

Front 855

True or False: Myotonic dystrophy is considered a trinucleotide expansion disease.

Back 855

True (remember: Try (trinucleotide) hunting for my fried eggs [X])

Front 856

True or False: Friedreich's ataxia is considered a trinucleotide expansion disease.

Back 856

True (remember: Try (trinucleotide) hunting for my fried eggs [X])

Front 857

True or False: Fragile X syndrome is considered a trinucleotide expansion disease.

Back 857

True (remember: Try (trinucleotide) hunting for my fried eggs [X])

Front 858

True or False: Duchenne's muscular dystrophy is considered a trinucleotide expansion disease.

Back 858

False; Duchenne's muscular dystrophy does not involve trinucleotide repeat expansion

Front 859

True or False: Achondroplasia is considered a trinucleotide expansion disease.

Back 859

False; achondroplasia does not involve trinucleotide repeat expansion
-- it is autosomal dominant and associated with advanced paternal age

Front 860

True or False: Trinucleotide repeat expansion diseases may show anticipation.

Back 860

true-- with successive generations the repeats and thus severity of the disease becomes worse and the age of onset becomes earlier

Front 861

Anticipation involves a(n) _____ (increase/decrease) in disease severity and a(n) _____ (earlier/later) age of onset in successive generations.

Back 861

increase; earlier

Front 862

Will a father with the fragile X gene pass on an expanded gene sequence to his children?

Back 862

No, germline expansion of this trinucleotide repeat occurs in females

Front 863

Myotonic dystrophy is associated with a _____ (CTG/CGG) repeat, while fragile X syndrome has a _____ (CTG/CGG) repeat.

Back 863

CTG; CGG (remember: myoTonic dystrophy = CTG, fraGile X = CGG)

Front 864

Huntington's disease has a _____ repeat, while Friedreich's ataxia is a repeat of _____ nucleotides.

Back 864

CAG; GAA

Front 865

What is the most common chromosomal disorder?

Back 865

down syndrome- trisomy 21

Front 866

True or False: Friedreich's ataxia is considered a trinucleotide expansion disease.

Back 866

True (remember: Try (trinucleotide) hunting for my fried eggs [X])

Front 867

True or False: Fragile X syndrome is considered a trinucleotide expansion disease.

Back 867

True (remember: Try (trinucleotide) hunting for my fried eggs [X])

Front 868

True or False: Duchenne's muscular dystrophy is considered a trinucleotide expansion disease.

Back 868

False; Duchenne's muscular dystrophy does not involve trinucleotide repeat expansion

Front 869

True or False: Achondroplasia is considered a trinucleotide expansion disease.

Back 869

False; achondroplasia does not involve trinucleotide repeat expansion
-- it is autosomal dominant and associated with advanced paternal age

Front 870

True or False: Trinucleotide repeat expansion diseases may show anticipation.

Back 870

true-- with successive generations the repeats and thus severity of the disease becomes worse and the age of onset becomes earlier

Front 871

Anticipation involves a(n) _____ (increase/decrease) in disease severity and a(n) _____ (earlier/later) age of onset in successive generations.

Back 871

increase; earlier

Front 872

Will a father with the fragile X gene pass on an expanded gene sequence to his children?

Back 872

No, germline expansion of this trinucleotide repeat occurs in females

Front 873

Myotonic dystrophy is associated with a _____ (CTG/CGG) repeat, while fragile X syndrome has a _____ (CTG/CGG) repeat.

Back 873

CTG; CGG (remember: myoTonic dystrophy = CTG, fraGile X = CGG)

Front 874

Huntington's disease has a _____ repeat, while Friedreich's ataxia is a repeat of _____ nucleotides.

Back 874

CAG; GAA

Front 875

What is the most common chromosomal disorder?

Back 875

down syndrome- trisomy 21

Front 876

A patient has a flat facial profile, prominent epicanthal folds, and a simian crease. This patient also has mental retardation. What is the most likely diagnosis?

Back 876

down syndrome

Front 877

A newborn is diagnosed with Down syndrome. She is vomiting bilious material. What is the most likely cause?

Back 877

duodenal atresia

Front 878

A newborn is diagnosed with Down syndrome. He has a heart murmur on examination. What is the most likely cause?

Back 878

atrial septal defect (ASD)

Front 879

What type of atrial septal defect is most common in patients with Down syndrome?

Back 879

septum-primum type

Front 880

Patients with Down syndrome who are more than 35 years old have an increased risk of what neurodegenerative disease?

Back 880

Alzheimer's disease

Front 881

Patients with Down syndrome have an increased risk of what type of leukemia?

Back 881

acute lymphoblastic/lymphocytic leukemia (ALL)

Front 882

Ninety-five percent of cases of Down syndrome are caused by the _____ of homologous chromosomes during the cell division process of _____.

Back 882

nondisjunction; meiosis

Front 883

Risk of having a baby with down syndrome is associated with what maternal factor?

Back 883

advanced maternal age

Front 884

True or False: More cases of Down syndrome are caused by Down mosaicism than by Robertsonian translocations.

Back 884

False; 4% of cases are caused by Robertsonian translocations, whereas only 1% are caused by Down mosaicism

Front 885

Prenatal testing reveals low levels of α-fetoprotein, high levels of β-human chorionic gonadotropin, and increased nuchal translucency. What is the most likely diagnosis?

Back 885

down syndrome

Front 886

What four substances are measured in the quad screen for Down syndrome?

Back 886

alpha fetoprotein, beta human chorionic gonadotropin, estriol, and inhibin A

Front 887

What would the levels of inhibin A and estriol be in maternal serum if the fetus has Down syndrome?

Back 887

inhibin A is increased; estriol is decreased

Front 888

True or False: Down syndrome that is a result of mosaicism is highly associated with maternal age.

Back 888

False; Down mosaicism does not have any maternal association

Front 889

Down syndrome is also known as trisomy _____.

Back 889

21 (remember: Drinking age = 21, Down syndrome)

Front 890

Which trisomy is the most common: 13 18, or 21?

Back 890

21 (1:700)

Front 891

Which trisomy is the least common: 13, 18, or 21?

Back 891

13 (1:15,000)

Front 892

What is the other name for trisomy 18?

Back 892

Edwards' syndrome (remember: Election age = 18)

Front 893

A baby has low-set ears, micrognathia, a prominent occiput, rocker bottom feet, and clenched hands. What is the most likely diagnosis?

Back 893

Edwards' syndrome - trisomy 18

Front 894

True or False: Trisomy 18 is associated with normal intellectual capacity but many dysmorphic features, such as rocker bottom feet, micrognathia, and a prominent occiput.

Back 894

False; trisomy 18 is associated with severe mental retardation

Front 895

True or False: It is common for patients with trisomy 18 to live into early adolescence.

Back 895

False; patients with trisomy 18 usually die within the first year of life

Front 896

A newborn has microphthalmia, microcephaly, cleft lip, cleft palate, and polydactyly. What is the most likely diagnosis?

Back 896

patau's syndrome- trisomy 13

Front 897

Patau's syndrome is also known as trisomy _____.

Back 897

13 (remember: Puberty = 13, Patau)

Front 898

True or False: Trisomy 13 is associated with cardiac defects and abnormal forebrain structures.

Back 898

true- holoprocencephaly- forebrain fails to develop into 2 hemispheres

Front 899

True or False: Newborns with trisomy 13 and newborns with trisomy 18 have similar expected life spans.

Back 899

True; infants with both of these conditions are expected to die before the age of 1 year

Front 900

The life expectancy for patients with trisomy 21 is _____ (<1 year/20-40 years/45-50 years).

Back 900

45-50 years

Front 901

True or False: Edward's syndrome is the least common autosomal trisomy.

Back 901

False; the incidence of Patau's is 1:15,000, less than that of Edward's syndrome, which is 1:8000

Front 902

What is a Robertsonian translocation?

Back 902

It is a nonreciprocal translocation of chromosome pairs, such that chromosomes carry genetic information in an uneven manner

Front 903

Name 5 chromosomes commonly involved in Robertsonian translocations.

Back 903

13, 14, 15, 21, 22

Front 904

What makes chromosomes 13, 14, 15, 21, and 22 candidates for Robertsonian translocations?

Back 904

They are acrosomal chromosomes, which means that the centromere is located near one end rather than in the middle

Front 905

How do acrosomal chromosomes align to create a Robertsonian translocation?

Back 905

The long arms match up and fuse at the centromere, losing the short arms of the chromosomes

Front 906

Does a Robertsonian translocation always result in a loss of genetic material?

Back 906

A balanced translocation retains all genetic material and will not have any abnormal phenotype; if the translocation is unbalanced, genetic material is lost and abnormalities result

Front 907

True or False: An unbalanced Robertsonian translocation may cause a chromosomal imbalance, but rarely miscarriage or stillbirth.

Back 907

False; unbalanced translocations may result in miscarriage, stillbirth, or chromosomal imbalance such as Down or Patau's syndrome

Front 908

The two types of chromosomal inversions are called _______ and _____inversions.

Back 908

pericentric, paracentric

Front 909

In chromosomal inversions, _____ (pericentric/paracentric) inversion involves the centromere.

Back 909

pericentric (perIcentric = Includes the centromere)

Front 910

In chromosomal inversions, _____ (pericentric/paracentric) inversion proceeds through meiosis.

Back 910

pericentric-- because it includes the centromere and centromeres are needed for meiosis

Front 911

In chromosomal inversions, _____ (pericentric/paracentric) inversion does not involve the centromere.

Back 911

paracentric

Front 912

In chromosomal inversions, _____ (pericentric/paracentric) inversion does not proceed through meiosis.

Back 912

paracentric- does not include the centromere and thus cannot complete meiosis

Front 913

How does a chromosomal inversion modify the affected chromosome?

Back 913

It reverses one segment of the chromosome end-to-end

Front 914

What is the effect of a chromosomal inversion on fertility?

Back 914

Fertility is decreased

Front 915

Cri-du-chat syndrome is caused by a deletion of the _____ arm of chromosome ____.

Back 915

short; 5

Front 916

The deletion of the short arm of chromosome 5 leads to what disease?

Back 916

cri-du-chat syndrome

Front 917

A newborn has microcephaly and epicanthal folds and produces a high-pitched crying or mewing sound. What is the most likely diagnosis?

Back 917

cri-du-chat syndrome

Front 918

True or False: Cri-du-chat syndrome is associated with cardiac abnormalities.

Back 918

true

Front 919

True or False: Patients with cri-du-chat syndrome are expected to have normal intelligence.

Back 919

False; cri-du-chat syndrome is associated with severe mental retardation

Front 920

What disease is caused by a microdeletion of the long arm of chromosome 7?

Back 920

william's syndrome

Front 921

Among others, what connective tissue gene is deleted in Williams syndrome?

Back 921

elastin

Front 922

Patients with Williams syndrome typically have _____ (coarse/masked/elfin) facies.

Back 922

elfin

Front 923

A patient has an extreme friendliness towards strangers and cheerful disposition, with noted mental retardation and cardiovascular disease; what is the diagnosis?

Back 923

william's syndrome

Front 924

In spite of their mental retardation, in which cognitive area are patients with Williams syndrome typically advanced?

Back 924

Patients with Williams syndrome typically have well-developed verbal skills

Front 925

Microdeletions at chromosome 22q11 can present as a spectrum of diseases including which two recognized syndromes?

Back 925

DiGeorge syndrome or velocardiofacial syndrome

Front 926

What disease is caused by microdeletions at 22q11 and involves defects of the thymus, the parathyroid, and the heart?

Back 926

DiGeorge syndrome

Front 927

What disease is caused by microdeletions at 22q11 and involves defects of the palate, the face, and the heart?

Back 927

velocardiofacial syndrome

Front 928

True or False: 22q11 syndromes are associated with cleft palate.

Back 928

true

Front 929

True or False: 22q11 syndromes are associated with abnormal facies.

Back 929

true

Front 930

True or False: 22q11 syndromes are associated with thymic aplasia.

Back 930

true

Front 931

True or False: 22q11 syndromes are associated with cardiac defects.

Back 931

true

Front 932

True or False: 22q11 Syndromes are associated with B cell deficiency.

Back 932

False; 22q11 syndromes are associated with T lymphocyte deficiency due to thymic aplasia

Front 933

True or False: 22q11 syndromes are associated with thyroid aplasia.

Back 933

False; 22q11 syndromes are associated with parathyroid aplasia

Front 934

True or False: 22q11 Syndromes are associated with hypercalcemia.

Back 934

False; 22q11 syndromes are associated with hypocalcemia due to parathyroid aplasia

Front 935

Name 5 findings associated with 22q11 deletion syndromes.

Back 935

Cleft palate, Abnormal facies, Thymic aplasia, Cardiac defects, Hypocalcemia secondary to parathyroid aplasia (CATCH-22)

Front 936

What embryonic structures are altered in 22q11 syndromes?

Back 936

These syndromes are due to aberrant development of the 3rd and 4th branchial pouches

Front 937

True or False: 22q11 Syndromes are X-linked recessive and show anticipation.

Back 937

False; 22q11 syndromes are due to microdeletions on chromosome 22 and have variable presentations

Front 938

Is vitamin A fat soluble or water soluble?

Back 938

fat soluble

Front 939

Is vitamin D fat soluble or water soluble?

Back 939

fat soluble

Front 940

Is vitamin E fat soluble or water soluble?

Back 940

fat soluble

Front 941

Is vitamin K fat soluble or water soluble?

Back 941

fat soluble

Front 942

Vision is associated with which fat-soluble vitamin?

Back 942

vitamin A

Front 943

Bone calcification is associated with which fat-soluble vitamin?

Back 943

Vitamin D

Front 944

Calcium homeostasis is associated with which fat-soluble vitamin?

Back 944

Vitamin D

Front 945

Clotting factors are associated with which fat-soluble vitamin?

Back 945

vitamin K

Front 946

The most abundant form of which fat-soluble vitamin acts as an antioxidant?

Back 946

Vitamin E

Front 947

Is vitamin B1 fat soluble or water soluble?

Back 947

water soluble

Front 948

Are vitamins B2, B3, B5 and B6 fat soluble or water soluble?

Back 948

water soluble

Front 949

Is vitamin B12 fat soluble or water soluble?

Back 949

water soluble

Front 950

Is biotin fat soluble or water soluble?

Back 950

water soluble

Front 951

Is folate fat soluble or water soluble?

Back 951

water soluble

Front 952

Is vitamin C fat soluble or water soluble?

Back 952

water soluble

Front 953

Is thiamine fat soluble or water soluble?

Back 953

Water soluble
thiamine = vitamin B1

Front 954

Is riboflavin fat soluble or water soluble?

Back 954

water soluble
riboflavin = vitamin B2

Front 955

Is pantothenic acid fat soluble or water soluble?

Back 955

water soluble
panthothenic acid = vitamin B5

Front 956

Is cobalamin fat soluble or water soluble?

Back 956

water soluble
cobalamine = vitamin B12

Front 957

Are pyridoxine, pyridoxal, and pyridoxamine fat soluble or water soluble?

Back 957

water soluble
pyridoxine = vitamin B6

Front 958

Is ascorbic acid fat soluble or water soluble?

Back 958

water soluble
ascorbic acid = vitamin C

Front 959

Which two water-soluble vitamins are associated with megaloblastic anemia?

Back 959

folate and vitamin B12/cobalamine

Front 960

Deficiency of which two water-soluble vitamins can cause macrocytic anemia?

Back 960

folate and vitamin B12/cobalamine

Front 961

Which water-soluble vitamin is associated with collagen synthesis?

Back 961

Vitamin C (ascorbic acid)

Front 962

Name two vitamins that serve as antioxidants.

Back 962

Vitamin E and vitamin C
(vitamin A can too)

Front 963

The vitamin precursor to thiamine pyrophosphate is _____ (fat / water) soluble.

Back 963

water- thiamine (vit B1)

Front 964

The vitamin precursor to flavin adenine dinucleotide and flavin mononucleotide is _____ (fat / water) soluble.

Back 964

water- riboflavin (vit B2)

Front 965

The vitamin precursor to oxidized nicotinamide adenine dinucleotide is _____ (fat / water) soluble.

Back 965

water- niacin (vit B3)

Front 966

The vitamin precursor to coenzyme A is _____ (fat / water) soluble.

Back 966

water- pantothenic acid (vit B5)

Front 967

The vitamin precursor to pyridoxal phosphate is _____ (fat / water) soluble.

Back 967

water- pyridoxine (vit B6)

Front 968

Are the B-complex vitamins fat soluble or water soluble?

Back 968

water- soluble

Front 969

True or False: Biotin, folate, and vitamins C, A, and B12 are all water-soluble vitamins.

Back 969

False; vitamin A is fat soluble, the rest are water soluble

Front 970

All of the water-soluble vitamins easily wash out from the body, except for which two?

Back 970

Vitamin B12 and folate (stored in the liver)

Front 971

In which organ is folate stored?

Back 971

liver

Front 972

Excess vitamin C is _____ (excreted/stored), and excess vitamin B12 is _____ (excreted/stored).

Back 972

excreted; stored

Front 973

B-complex deficiencies often result in what three conditions?

Back 973

dermatitis, glossitis and diarrhea

Front 974

What is another name for vitamin A?

Back 974

Retinol (remember Retinol is Vitamin-A, so think Retin-A)

Front 975

True or False: A deficiency of vitamin A (retinol) leads to night blindness.

Back 975

true

Front 976

True or False: A deficiency of vitamin A (retinol) leads to dry skin.

Back 976

true

Front 977

Vitamin A is a constituent of what visual pigment?

Back 977

retinal

Front 978

What are the symptoms of vitamin A intoxication?

Back 978

Vitamin A excess is associated with arthralgias, fatigue, headaches, skin changes, sore throat, and alopecia

Front 979

True or False: Vitamin A deficiency is associated with arthralgias, fatigue, headaches, skin changes, sore throat, and alopecia.

Back 979

False; these symptoms are associated with an excess of Vitamin A

Front 980

What foods contain high amounts of vitamin A?

Back 980

Vitamin A is found in liver (esp polar bear liver), and in leafy vegetables

Front 981

Name two topical uses of vitamin A.

Back 981

It can be used topically for wrinkles and for acne

Front 982

What are the effects of taking large amounts of vitamin A during pregnancy?

Back 982

It is a teratogen, and causes cleft palate and cardiac abnormalities

Front 983

What is another name for vitamin B1?

Back 983

thiamine

Front 984

Beriberi is caused by a deficiency of which vitamin?

Back 984

vitamin B1/ thiamine (spell beriberi as Ber1Ber1)

Front 985

Wernicke-Korsakoff syndrome is caused by a deficiency of which vitamin?

Back 985

vitamin B1/ thiamine

Front 986

The vitamin precursor to coenzyme A is _____ (fat / water) soluble.

Back 986

water- pantothenic acid (vit B5)

Front 987

The vitamin precursor to pyridoxal phosphate is _____ (fat / water) soluble.

Back 987

water- pyridoxine (vit B6)

Front 988

Are the B-complex vitamins fat soluble or water soluble?

Back 988

water- soluble

Front 989

True or False: Biotin, folate, and vitamins C, A, and B12 are all water-soluble vitamins.

Back 989

False; vitamin A is fat soluble, the rest are water soluble

Front 990

All of the water-soluble vitamins easily wash out from the body, except for which two?

Back 990

Vitamin B12 and folate (stored in the liver)

Front 991

In which organ is folate stored?

Back 991

liver

Front 992

Excess vitamin C is _____ (excreted/stored), and excess vitamin B12 is _____ (excreted/stored).

Back 992

excreted; stored

Front 993

B-complex deficiencies often result in what three conditions?

Back 993

dermatitis, glossitis and diarrhea

Front 994

What is another name for vitamin A?

Back 994

Retinol (remember Retinol is Vitamin-A, so think Retin-A)

Front 995

True or False: A deficiency of vitamin A (retinol) leads to night blindness.

Back 995

true

Front 996

True or False: A deficiency of vitamin A (retinol) leads to dry skin.

Back 996

true

Front 997

Vitamin A is a constituent of what visual pigment?

Back 997

retinal

Front 998

What are the symptoms of vitamin A intoxication?

Back 998

Vitamin A excess is associated with arthralgias, fatigue, headaches, skin changes, sore throat, and alopecia

Front 999

True or False: Vitamin A deficiency is associated with arthralgias, fatigue, headaches, skin changes, sore throat, and alopecia.

Back 999

False; these symptoms are associated with an excess of Vitamin A

Front 1000

What foods contain high amounts of vitamin A?

Back 1000

Vitamin A is found in liver (esp polar bear liver), and in leafy vegetables

Front 1001

Name two topical uses of vitamin A.

Back 1001

It can be used topically for wrinkles and for acne

Front 1002

What are the effects of taking large amounts of vitamin A during pregnancy?

Back 1002

It is a teratogen, and causes cleft palate and cardiac abnormalities

Front 1003

What is another name for vitamin B1?

Back 1003

thiamine

Front 1004

Beriberi is caused by a deficiency of which vitamin?

Back 1004

vitamin B1/ thiamine (spell beriberi as Ber1Ber1)

Front 1005

Wernicke-Korsakoff syndrome is caused by a deficiency of which vitamin?

Back 1005

vitamin B1/ thiamine

Front 1006

True or False: A deficiency of vitamin A (retinol) leads to dry skin.

Back 1006

true

Front 1007

Vitamin A is a constituent of what visual pigment?

Back 1007

retinal

Front 1008

What are the symptoms of vitamin A intoxication?

Back 1008

Vitamin A excess is associated with arthralgias, fatigue, headaches, skin changes, sore throat, and alopecia

Front 1009

True or False: Vitamin A deficiency is associated with arthralgias, fatigue, headaches, skin changes, sore throat, and alopecia.

Back 1009

False; these symptoms are associated with an excess of Vitamin A

Front 1010

What foods contain high amounts of vitamin A?

Back 1010

Vitamin A is found in liver (esp polar bear liver), and in leafy vegetables

Front 1011

Name two topical uses of vitamin A.

Back 1011

It can be used topically for wrinkles and for acne

Front 1012

What are the effects of taking large amounts of vitamin A during pregnancy?

Back 1012

It is a teratogen, and causes cleft palate and cardiac abnormalities

Front 1013

What is another name for vitamin B1?

Back 1013

thiamine

Front 1014

Beriberi is caused by a deficiency of which vitamin?

Back 1014

vitamin B1/ thiamine (spell beriberi as Ber1Ber1)

Front 1015

Wernicke-Korsakoff syndrome is caused by a deficiency of which vitamin?

Back 1015

vitamin B1/ thiamine

Front 1016

Vitamin B1 is the precursor to what cofactor?

Back 1016

thyamine pyrophosphate (TPP)

Front 1017

What vitamin is needed for the decarboxylation of α-ketoacids like pyruvate and α-ketoglutarate?

Back 1017

vitamin B1 (thiamine)-- to make cofactor thyamine pyrophosphate (TPP)

Front 1018

What is the role of thiamine in the TCA cycle?

Back 1018

It is a cofactor for α-ketoglutarate dehydrogenase

Front 1019

Which step in glycolysis requires thiamine?

Back 1019

TPP is needed as a cofactor for pyruvate dehydrogenase

Front 1020

What vitamin is needed as a cofactor for branched-chain amino acid dehydrogenase?

Back 1020

Vitamin B1 (thiamine)

Front 1021

What vitamin is needed for the activity of transketolase in the hexose monophosphate shunt?

Back 1021

Vitamin B1 (thiamine)

Front 1022

Are polyneuritis and muscle wasting characteristic of wet or dry beriberi?

Back 1022

dry beriberi

Front 1023

Is high-output cardiac failure caused by dilated cardiomyopathy and edema characteristic of wet or dry beriberi?

Back 1023

wet beriberi

Front 1024

True or False: Vitamin B1 deficiency in alcoholism occurs due to a reducing reaction between ethanol and thiamine.

Back 1024

False; the deficiency is secondary to malnutrition and malabsorption

Front 1025

A patient in the emergency room who has recent onset ophthalmoplegia, confusion, and ataxia; you suspect what disease process?

Back 1025

This is typical for Wernicke-Korsakoff syndrome

Front 1026

Name at least 4 neurologic symptoms seen in Wernicke-Korsakoff syndrome.

Back 1026

opthalmoplegia, ataxia, confusion, confabulations, memory loss, personality change

Front 1027

What is another name for vitamin B2?

Back 1027

riboflavin

Front 1028

Riboflavin is another name for what vitamin?

Back 1028

vitamin B2

Front 1029

Cheilosis and corneal vascularization occur as a result of a deficiency of which vitamin?

Back 1029

vitamin b2- riboflavin remember: the 2 C's)

Front 1030

What is cheilosis?

Back 1030

Inflammation of the lips, with scaling and fissures at the corners of the mouth; this is seen in vitamin B2 deficiency

Front 1031

Flavin adenine dinucleotide is derived from which vitamin?

Back 1031

riboflavin- vitamin B2 (remember: FAD and FMN are derived from riboFlavin, B2 = 2 ATP)

Front 1032

Flavin mononucleotide is derived from which vitamin?

Back 1032

riboFlavin- vitamin B2

Front 1033

True or False: Vitamin B2 gives rise to cofactors that participate in oxidation-reduction reactions.

Back 1033

true (FAD+ and FADH2)

Front 1034

What is another name for vitamin B3?

Back 1034

niacin

Front 1035

A deficiency of vitamin B3 (niacin) leads to what disease?

Back 1035

pellagra

Front 1036

Pellagra can be caused by what disease, which is caused by decreased tryptophan absorption?

Back 1036

Hartnup's disease

Front 1037

Pellagra can be caused by what syndrome, characterized by increased tryptophan metabolism?

Back 1037

malignant carcinoid syndrome

Front 1038

Pellagra can be caused by which drug as a result of decreased levels of vitamin B6 (pyridoxine)?

Back 1038

isoniazid (INH) for treatment of TB

Front 1039

How does isoniazid cause a niacin deficiency?

Back 1039

By depleting vitamin B6, the synthesis of niacin from tryptophan cannot occur

Front 1040

A patient being treated for hyperlipidemia complains of becoming red in the face after taking his medication; what drug is he taking?

Back 1040

niacin (vitamin b3)

Front 1041

What vitamin is the precursor of oxidized nicotinamide adenine dinucleotide and oxidized nicotinamide adenine dinucleotide phosphate?

Back 1041

niacin (vitamin B3)

Front 1042

What vitamin is the precursor of oxidized nicotinamide adenine dinucleotide and oxidized nicotinamide adenine dinucleotide phosphate?

Back 1042

Vitamin B3 (niacin) (remember: NAD derived from Niacin, B3 = 3 ATP)

Front 1043

Vitamin B3 can be derived from the amino acid _____ using vitamin ____.

Back 1043

tryptophan; vitamin B6 (pyridoxine)

Front 1044

What amino acid acts as the precursor of vitamin B3?

Back 1044

tryptophan

Front 1045

A patient has Hartnup's disease, causing malabsorption of neutral amino acids; what vitamin deficiency could occur?

Back 1045

niacin (vitamin B3)

Front 1046

What are the "3 D's" of pellagra?

Back 1046

diarrhea, dermatitis, dementia

Front 1047

True or False: In addition to diarrhea, dermatitis, and dementia, pellagra is also characterized by beefy glossitis.

Back 1047

true

Front 1048

What is another name for vitamin B5?

Back 1048

pantothenate (panthothenic acid)

Front 1049

What are the symptoms of vitamin B5 deficiency?

Back 1049

dermatitis, enteritis, alopecia, and adrenal insufficiency

Front 1050

What vitamin is a precursor of coenzyme A, a cofactor for acyl transfer?

Back 1050

vitamin B5- pantothenate (remember: pantothen-A is in Co-A)

Front 1051

What vitamin is a component of fatty acid synthase?

Back 1051

vitamin B5 (pantothenate)

Front 1052

Adrenal insufficiency may be caused by a deficiency of which vitamin?

Back 1052

vitamin B5 (pantothenate)

Front 1053

What is another name for vitamin B6?

Back 1053

pyridoxine

Front 1054

What are the symptoms of vitamin B6 deficiency?

Back 1054

Convulsions, hyperirritability, and peripheral neuropathy

Front 1055

A deficiency of vitamin B6 is inducible by what two drugs?

Back 1055

isoniazid (INH) and oral contraceptives (OCPs)

Front 1056

A 32-year-old man begins taking INH after a positive PPD. He presents with numbness and tingling in the extremities. What is the most likely cause of his peripheral neuropathy?

Back 1056

vitamin B6 deficiency due to INH

Front 1057

A 28-year-old presents to the ED with convulsions and hyperirritability one month after beginning treatment for tuberculosis. What deficiency is a possible cause of these symptoms?

Back 1057

vitamin B6 deficiency due to INH (isoniazid) therapy for TB

Front 1058

A 20-year-old woman is started on oral contraceptive pills for birth control. Soon after starting she reports numbness and tingling in the extremities. What deficiency is a possible cause of her peripheral neuropathy?

Back 1058

vitamin B6 deficiency induced by OCPs

Front 1059

Which vitamin is the precursor to pyridoxal phosphate?

Back 1059

vitamin B6 (pyridoxine)

Front 1060

Which vitamin is needed for transamination reactions?

Back 1060

vitamin B6 (pyridoxine)

Front 1061

Which vitamin is needed for decarboxylation reactions?

Back 1061

vitamin B6 (pyridoxine)

Front 1062

Which vitamin is needed as a cofactor for glycogen phosphorylase?

Back 1062

vitamin B6 (pyridoxine)

Front 1063

What vitamin is required for conversion of tryptophan to niacin?

Back 1063

vitamin B6 (pyridoxine)

Front 1064

Which vitamin is needed for heme synthesis?

Back 1064

vitamin B6 (pyridoxine)

Front 1065

Which vitamin is required for the synthesis of niacin from tryptophan?

Back 1065

vitamin B6 (pyridoxine)

Front 1066

A deficiency of _____ may be caused by the use of antibiotics or the ingestion of raw eggs.

Back 1066

biotin

Front 1067

What are the symptoms of biotin deficiency?

Back 1067

dermatitis, alopecia and enteritis

Front 1068

Biotin is required as a cofactor for _____ reactions.

Back 1068

carboxylation

Front 1069

What is another name for vitamin C?

Back 1069

Ascorbic acid

Front 1070

True or False: Biotin is a cofactor for the following reaction: conversion of pyruvate to oxaloacetate.

Back 1070

true

Front 1071

What disease is caused by a deficiency of vitamin C?

Back 1071

scurvy

Front 1072

True or False: Biotin is a cofactor for the follow reaction: acetyl-CoA → malonyl-CoA.

Back 1072

true

Front 1073

True or False: Biotin is a cofactor for the follow reaction: conversion of propionyl-CoA to methylmalonyl-CoA.

Back 1073

true

Front 1074

What enzyme requires a biotin cofactor to create oxaloacetate?

Back 1074

pyruvate carboxylase

Front 1075

What enzyme requires a biotin cofactor to create malonyl-CoA?

Back 1075

acetyl CoA carboxylase

Front 1076

What enzyme requires a biotin cofactor to create methylmalonyl-CoA?

Back 1076

Propionyl-CoA carboxylase

Front 1077

True or false: Biotin deficiency is a very common vitamin deficiency that results in dermatitis, alopecia, and enteritis

Back 1077

False; this is a rare deficiency, but when seen presents with dermatitis, alopecia, and enteritis

Front 1078

A patient has swollen gums, bruising, anemia, and poor wound healing. What vitamin deficiency is probably responsible for these symptoms?

Back 1078

vitamin C deficiency

Front 1079

List four symptoms that are associated with scurvy.

Back 1079

bruising, swollen gums, anemia, and poor wound healing

Front 1080

Vitamin C is needed for the addition of _____ groups to the amino acids lysine and proline during collagen synthesis.

Back 1080

hydroxyl

Front 1081

Vitamin C _____ (promotes/inhibits) iron absorption by keeping it in the _____ (reduced/oxidized) state, which is more absorbable.

Back 1081

promotes; reduced

Front 1082

True or False: Vitamin C is required for the conversion of dopamine to norepinephrine.

Back 1082

true- it is required as a cofactor for the enzyme dopamine beta hydroxylase (DBH)

Front 1083

How can a patient increase their dietary intake of vitamin C?

Back 1083

By eating more fruits and vegetables; British sailors carried limes to prevent scurvy (origin of the word "limey")

Front 1084

What function does vitamin C share with vitamin E?

Back 1084

Both are antioxidants

Front 1085

What enzyme uses ascorbic acid to convert dopamine to NE?

Back 1085

dopamine beta hydroxylase

Front 1086

Is vitamin D2 found in plants or produced in sun-exposed skin?

Back 1086

plants

Front 1087

What is another name for vitamin D2?

Back 1087

ergocalciferol

Front 1088

What form of vitamin D is found in vitamins and other pharmaceuticals?

Back 1088

Vitamin D2

Front 1089

Is vitamin D3 found in plants or produced in sun-exposed skin?

Back 1089

produced in sun-exposed skin

Front 1090

When drinking a glass of milk, what type of vitamin D are you absorbing?

Back 1090

Vitamin D3 (remember: drinking milk (fortified with vitamin D) is good for bones)

Front 1091

What is another name for vitamin D3?

Back 1091

cholecalciferol

Front 1092

What is the storage form of vitamin D?

Back 1092

25-OH D3

Front 1093

What is the active form of vitamin D3?

Back 1093

1,25- dihydroxy vitamin D3 = calcitriol

Front 1094

A deficiency of vitamin D causes what disease in children?

Back 1094

rickets- bending of bones

Front 1095

A deficiency of vitamin D causes what disease in adults?

Back 1095

osteomalacia (soft bones)

Front 1096

A deficiency of vitamin D may lead to ______ (hypocalcemia/hypercalcemia) and ______ (flaccid muscles/tetany).

Back 1096

hypocalcemia and tetany

Front 1097

Vitamin D increases the absorption of what two types of ions in the intestine?

Back 1097

calcium and phosphate

Front 1098

What is the effect of vitamin D on your bones?

Back 1098

it increases resorption

Front 1099

A patient has hypercalcemia, loss of appetite, and stupor. What vitamin excess is probably responsible for these symptoms?

Back 1099

vitamin D

Front 1100

In what disease do epithelioid macrophages convert vitamin D into its active form, leading to hypercalcemia?

Back 1100

sarcoidosis

Front 1101

A deficiency of vitamin E leads to the increased fragility of what cell type?

Back 1101

erythrocytes

Front 1102

True or False: Vitamin E protects erythrocytes from hemolysis.

Back 1102

True (remember: E is for Erythrocytes)
(as an antioxidant it protects them from free radical damage)

Front 1103

True or False: Vitamin E is an antioxidant.

Back 1103

true

Front 1104

What type of anemia is seen in vitamin E deficiency?

Back 1104

Hemolytic anemia

Front 1105

A patient presents with hemolytic anemia, muscle weakness, and neuropathy; what vitamin deficiency do you suspect?

Back 1105

vitamin E deficiency

Front 1106

Vitamin K deficiency leads to _____ (increased/decreased/normal) prothrombin time, _____ (increased/decreased/normal) activated partial thromboplastin time, and _____ (increased/decreased/normal) bleeding time.

Back 1106

increased; increased; normal

Front 1107

True or False: Vitamin K deficiency elevates prothrombin time.

Back 1107

true

Front 1108

True or False: Vitamin K deficiency elevates activated partial thromboplastin time.

Back 1108

true

Front 1109

True or False: Vitamin K deficiency elevates bleeding time.

Back 1109

False; vitamin K deficiency has no effect on bleeding time

Front 1110

True or False: Neonates are relatively deficient in vitamin K when they are born, which can predispose them to hemorrhage.

Back 1110

true-- so they get a vitamin K shot after birth (the gut bacteria makes the vitamin K and their gut flora is not fully developed)

Front 1111

What characteristic of neonates' intestines predisposes babies to hemorrhage? How is it prevented?

Back 1111

The neonatal intestine is sterile and thus cannot synthesize vitamin K; to prevent hemorrhage, all newborns are given a vitamin K injection at birth

Front 1112

Vitamin K is required for the ______ of the glutamic acid residues of factors II, VII, IX, and X and proteins C and S.

Back 1112

γ-Carboxylation

Front 1113

Which residues of factors II, VII, IX, and X and proteins C and S are γ-carboxylated by vitamin K?

Back 1113

Glutamic acid

Front 1114

Vitamin K is required for the γ-carboxylation of which four coagulation factors?

Back 1114

Factors II, VII, IX, and X

Front 1115

Vitamin K is required for which anticoagulation factors?

Back 1115

Proteins C and S

Front 1116

Which clotting factors are dependent on vitamin K?

Back 1116

Factors II, VII, IX, and X and proteins C and S

Front 1117

What synthesizes vitamin K in the gut?

Back 1117

Vitamin K is synthesized by intestinal bacteria

Front 1118

What is the effect of vitamin D on your bones?

Back 1118

it increases resorption

Front 1119

A patient has hypercalcemia, loss of appetite, and stupor. What vitamin excess is probably responsible for these symptoms?

Back 1119

vitamin D

Front 1120

In what disease do epithelioid macrophages convert vitamin D into its active form, leading to hypercalcemia?

Back 1120

sarcoidosis

Front 1121

A deficiency of vitamin E leads to the increased fragility of what cell type?

Back 1121

erythrocytes

Front 1122

True or False: Vitamin E protects erythrocytes from hemolysis.

Back 1122

True (remember: E is for Erythrocytes)
(as an antioxidant it protects them from free radical damage)

Front 1123

True or False: Vitamin E is an antioxidant.

Back 1123

true

Front 1124

What type of anemia is seen in vitamin E deficiency?

Back 1124

Hemolytic anemia

Front 1125

A patient presents with hemolytic anemia, muscle weakness, and neuropathy; what vitamin deficiency do you suspect?

Back 1125

vitamin E deficiency

Front 1126

Vitamin K deficiency leads to _____ (increased/decreased/normal) prothrombin time, _____ (increased/decreased/normal) activated partial thromboplastin time, and _____ (increased/decreased/normal) bleeding time.

Back 1126

increased; increased; normal

Front 1127

True or False: Vitamin K deficiency elevates prothrombin time.

Back 1127

true

Front 1128

True or False: Vitamin K deficiency elevates activated partial thromboplastin time.

Back 1128

true

Front 1129

True or False: Vitamin K deficiency elevates bleeding time.

Back 1129

False; vitamin K deficiency has no effect on bleeding time

Front 1130

True or False: Neonates are relatively deficient in vitamin K when they are born, which can predispose them to hemorrhage.

Back 1130

true-- so they get a vitamin K shot after birth (the gut bacteria makes the vitamin K and their gut flora is not fully developed)

Front 1131

What characteristic of neonates' intestines predisposes babies to hemorrhage? How is it prevented?

Back 1131

The neonatal intestine is sterile and thus cannot synthesize vitamin K; to prevent hemorrhage, all newborns are given a vitamin K injection at birth

Front 1132

Vitamin K is required for the ______ of the glutamic acid residues of factors II, VII, IX, and X and proteins C and S.

Back 1132

γ-Carboxylation

Front 1133

Which residues of factors II, VII, IX, and X and proteins C and S are γ-carboxylated by vitamin K?

Back 1133

Glutamic acid

Front 1134

Vitamin K is required for the γ-carboxylation of which four coagulation factors?

Back 1134

Factors II, VII, IX, and X

Front 1135

Vitamin K is required for which anticoagulation factors?

Back 1135

Proteins C and S

Front 1136

Which clotting factors are dependent on vitamin K?

Back 1136

Factors II, VII, IX, and X and proteins C and S

Front 1137

What synthesizes vitamin K in the gut?

Back 1137

Vitamin K is synthesized by intestinal bacteria

Front 1138

True or False: Vitamin K deficiency can occur after the prolonged use of antibiotics.

Back 1138

true since it wipes out the gut flora that make the vit K

Front 1139

What drug is a vitamin K antagonist?

Back 1139

warfarin (coumadin)

Front 1140

A patient has delayed wound healing, hypogonadism, and decreased axillary, facial, and pubic hair. What nutritional deficiency is likely to be responsible for these symptoms?

Back 1140

zinc deficiency

Front 1141

True or False: Zinc deficiency may predispose an individual to alcoholic cirrhosis.

Back 1141

true

Front 1142

True or False: Zinc deficiency is associated with decreased axillary, facial, and pubic hair.

Back 1142

true

Front 1143

True or False: Zinc deficiency is associated with hypergonadism.

Back 1143

False; zinc deficiency is associated with hypogonadism

Front 1144

What is the importance of zinc fingers?

Back 1144

Zinc fingers allow transcription factors and other molecules to interact with DNA

Front 1145

What is the limiting reagent in alcohol metabolism?

Back 1145

Nicotinamide adenine dinucleotide (NAD+)

Front 1146

What intermediate of alcohol metabolism accumulates when a person takes the drug disulfiram?

Back 1146

acetaldehyde

Front 1147

What enzyme does disulfiram inhibit?

Back 1147

Acetaldehyde dehydrogenase

Front 1148

True or False: Disulfiram produces symptoms of nausea, vomiting, and headache as a result of the accumulation of acetaldehyde.

Back 1148

true

Front 1149

A patient taking fomepizole would have a decreased accumulation of _____ because it inhibits _____.

Back 1149

acetaldehyde; alcohol dehydrogenase; fomepizole is used in cases of methanol poisoning

Front 1150

Where in the cell is the reaction that is inhibited by fomepizole?

Back 1150

Fomepizole blocks the action of alcohol dehydrogenase, which is in the cytosol

Front 1151

Where in the cell is the reaction that is inhibited by disulfiram?

Back 1151

Disulfiram inhibits acetaldehyde dehydrogenase, which is in the mitochondria

Front 1152

What happens to the rate of ethanol metabolism by alcohol dehydrogenase as more ethanol is consumed?

Back 1152

There is no change in the rate since this reaction proceeds by zero-order kinetics

Front 1153

Ethanol metabolism _____ (increases/decreases) the NADH/NAD+ ratio in the liver, which _____ (promotes/inhibits) gluconeogenesis.

Back 1153

increases; inhibits

Front 1154

Ethanol ingestion leads to the increased conversion of pyruvate to _____ and oxaloacetate to _____, because these reactions regenerate NAD+ from NADH.

Back 1154

lactate; malate

Front 1155

The high NADH/NAD+ ratio seen after ethanol ingestion is responsible for the shunting of metabolites away from _____ and toward _____ _____ synthesis.

Back 1155

Gluconeogenesis; fatty acid

Front 1156

Ethanol metabolism ultimately results in _____ as a result of the inhibition of gluconeogenesis, and hepatocellular _____ from increased fatty acid synthesis.

Back 1156

Hypoglycemia, steatosis

Front 1157

What by-product of ethanol metabolism is responsible for hepatic steatosis?

Back 1157

The accumulation of NADH drives pyruvate to lactate and oxaloacetate to malate, resulting in decreased gluconeogenesis and increased fatty acid synthesis

Front 1158

Kwashiorkor is the result of a deficiency of _____ in the diet.

Back 1158

protein

Front 1159

A malnourished child is also anemic, edematous, and has elevated LFTs; what is the diagnosis?

Back 1159

kwashiorkor (remember: Kwashiorkor results from a protein-deficient MEAL: Malnutrition, Edema, Anemia, Liver (fatty))

Front 1160

True or False: Kwashiorkor is associated with skin lesions.

Back 1160

true

Front 1161

True or False: Kwashiorkor is associated with fatty change of the liver.

Back 1161

true

Front 1162

True or False: Kwashiorkor is associated with edema.

Back 1162

true

Front 1163

A malnourished child has a swollen, edematous belly. Is she more likely to have kwashiorkor or marasmus?

Back 1163

Kwashiorkor

Front 1164

Marasmus is the result of a deficiency of _____ in the diet.

Back 1164

Calories (all nutrients)

Front 1165

A child presents with tissue and muscle wasting, loss of subcutaneous fat, and variable edema. Is she more likely to have kwashiorkor or marasmus?

Back 1165

marasmus

Front 1166

A malnourished child has significant tissue wasting. Is she more likely to have kwashiorkor or marasmus?

Back 1166

Marasmus (remember: Marasmus results in Muscle wasting)

Front 1167

Kwashiorkor is a deficiency of _____ that results in skin lesions, anemia, edema, and liver malfunction (fatty change). By contrast, marasmus is a deficiency of _____ that results in tissue wasting.

Back 1167

protein; calories

Front 1168

Fatty acid oxidation occurs in the _____ (mitochondria/cytoplasm), whereas fatty acid synthesis occurs in the _____ (mitochondria/cytoplasm).

Back 1168

mitchondria; cytoplasm

Front 1169

Glycolysis occurs in the _____ (mitochondria/cytoplasm), whereas the Krebs cycle occurs in the _____ (mitochondria/cytoplasm).

Back 1169

cytoplasm; mitochondria

Front 1170

Where in the cell are the enzymes of the hexose monophosphate shunt located?

Back 1170

cytoplasm

Front 1171

Where in the cell does acetyl coenzyme A production occur?

Back 1171

mitochondria

Front 1172

Protein synthesis occurs on the _____ (rough/smooth) endoplasmic reticulum, whereas steroid synthesis occurs on the _____ (rough/smooth) endoplasmic reticulum.

Back 1172

rough; smooth

Front 1173

Name the three pathways that occur in both the cytoplasm and the mitochondria.

Back 1173

Heme synthesis, Urea cycle, Gluconeogenesis (remember the mnemonic: HUGs take two)

Front 1174

Name four pathways that occur in the mitochondria.

Back 1174

Fatty acid oxidation, acetyl-CoA production, Krebs cycle, and oxidative phosphorylation

Front 1175

Fatty acid oxidation occurs in the _____ (mitochondria/cytoplasm).

Back 1175

mitochrondia

Front 1176

Acetyl-CoA production occurs in the _____ (mitochondria/cytoplasm).

Back 1176

mitochondria

Front 1177

The Krebs cycle occurs in the _____ (mitochondria/cytoplasm).

Back 1177

mitochondria

Front 1178

What enzyme uses ATP to add a high-energy phosphate group onto a substrate?

Back 1178

kinase

Front 1179

what enzyme adds inorganic phosphate onto substrate without using ATP?

Back 1179

phosphorylase

Front 1180

what enzyme removes phosphate group from substrates?

Back 1180

phosphatase

Front 1181

what enzyme oxidizes substrates?

Back 1181

dehydrogenase

Front 1182

what enzyme adds 1 carbon with the help biotin to substrates?

Back 1182

carboxylase

Front 1183

What is the rate-determining enzyme of de novo pyrimidine synthesis?

Back 1183

carbamoyl phosphate synthetase II

Front 1184

carbamoyl phosphate synthetase II is the rate-limiting enzyme of which metabolic process?

Back 1184

de novo pyrimidine synthesis

Front 1185

What is the rate-determining enzyme of de novo purine synthesis?

Back 1185

glutamine-PRPP amidotransferase

Front 1186

Glutamine-PRPP amidotransferase is the rate-limiting enzyme of which metabolic process?

Back 1186

de novo purine synthesis

Front 1187

What is the rate-determining enzyme of glycolysis?

Back 1187

phosphofructokinase-1 (PFK-1)

Front 1188

Phosphofructokinase-1 is the rate-limiting enzyme of which metabolic process?

Back 1188

glycolysis

Front 1189

What is the rate-determining enzyme of gluconeogenesis?

Back 1189

fructose- 1,6 bisphosphatase

Front 1190

fructose- 1,6 bisphosphatase is the rate-limiting enzyme of which metabolic process?

Back 1190

gluconeogenesis

Front 1191

What is the rate-determining enzyme of the TCA cycle?

Back 1191

isocitrate dehydrogenase

Front 1192

Isocitrate dehydrogenase is the rate-limiting enzyme of which metabolic process?

Back 1192

TCA/Krebs cycle

Front 1193

What is the rate-determining enzyme of glycogen synthesis?

Back 1193

glycogen synthase

Front 1194

Glycogen synthase is the rate-limiting enzyme of which metabolic process?

Back 1194

glycogen synthesis

Front 1195

What is the rate-determining enzyme of glycogenolysis?

Back 1195

glycogen phosphorylase

Front 1196

Glycogen phosphorylase is the rate-limiting enzyme of which metabolic process?

Back 1196

glycogenolysis

Front 1197

What is the rate-determining enzyme of the HMP shunt?

Back 1197

glucose 6 phosphate dehydrogenase (G6PD)

Front 1198

Glucose-6-phosphate dehydrogenase is the rate-limiting enzyme of which metabolic process?

Back 1198

the HMP shunt (purpose is to provide NADPH for reductive reactions like glutatione inside RBCs)

Front 1199

What is the rate-determining enzyme of fatty acid synthesis?

Back 1199

acetyl-CoA carboxylase (ACC)

Front 1200

Acetyl-CoA carboxylase is the rate-limiting enzyme of which metabolic process?

Back 1200

fatty acid synthesis

Front 1201

What is the rate-determining enzyme of fatty acid oxidation?

Back 1201

carnitine acyltransferase I

Front 1202

Carnitine acyltransferase I is the rate-limiting enzyme of which metabolic process?

Back 1202

Fatty acid oxidation

Front 1203

What is the rate-determining enzyme of ketogenesis?

Back 1203

HMG-CoA synthase

Front 1204

HMG-CoA synthase is the rate-limiting enzyme of which metabolic process?

Back 1204

ketogenesis

Front 1205

What is the rate-determining enzyme of cholesterol synthesis?

Back 1205

HMG CoA reductase (statins inhibit this)

Front 1206

HMG-CoA reductase is the rate-limiting enzyme of which metabolic process?

Back 1206

cholesterol synthesis

Front 1207

What is the rate-determining enzyme of the urea cycle?

Back 1207

carbamoyl phosphate synthetase I

Front 1208

Carbamoyl phosphate synthetase is the rate-limiting enzyme of which metabolic process?

Back 1208

urea cycle

Front 1209

What is the name of the molecule that is composed of adenine, ribose, three phosphoryl groups, and two phosphoanhydride bonds?

Back 1209

ATP

Front 1210

In which two organs are ATPs produced from the aerobic metabolism of glucose via the malate-aspartate shuttle?

Back 1210

heart and liver

Front 1211

How many ATP molecules are produced from the aerobic metabolism of glucose via the malate-aspartate shuttle?

Back 1211

32 ATP (this is NADH entering the mitochondria from the cytosol-- if it uses this shuttle it yields 3 ATP per NADH)

Front 1212

How many ATP molecules are produced from the aerobic metabolism of glucose via the glyceraldehyde-3-phosphate shuttle?

Back 1212

30 ATP- this occurs in muscle

Front 1213

More ATP molecules are produced from glucose if the _____ (malate-aspartate shuttle/glyceraldehyde-3-phosphate shuttle) is used.

Back 1213

malate-aspartate shuttle

Front 1214

Where does the energy come from in order to proceed from substrate to product in energetically unfavorable reactions?

Back 1214

The hydrolysis of ATP can be coupled with energetically unfavorable reactions to produce enough net energy

Front 1215

What is the net gain of ATP molecules after a molecule of glucose has participated in anaerobic glycolysis?

Back 1215

2 ATP the NADH created cannot be used to generate energy without oxygen

Front 1216

A glucose molecule is metabolized to the level of pyruvate and lactate; is this process an anaerobic or aerobic process?

Back 1216

An anaerobic process; no oxygen has been used in this reaction

Front 1217

Which ion helps stabilize the charged phosphoryl groups in the triphosphate moiety of ATP?

Back 1217

Mg2+

Front 1218

Name the three carriers of electrons.

Back 1218

NADH, NADPH, FADH2

Front 1219

What compounds are used as single-carbon donors in various reactions?

Back 1219

Tetrahydrofolates

Front 1220

What vitamin is the donor of the carboxyl group used in many biochemical reactions in the body?

Back 1220

biotin

Front 1221

What is the activated carrier for phosphoryl groups?

Back 1221

ATP

Front 1222

What molecule donates methyl groups?

Back 1222

S-adenosylmethionine (SAM)

Front 1223

Which activated carrier molecule donates aldehyde groups?

Back 1223

Thiamin pyrophosphate (TPP)

Front 1224

Acyl groups are transported using which two activated carriers?

Back 1224

Coenzyme A and lipoamide

Front 1225

What pathway produces NADPH?

Back 1225

The hexose monophosphate (HMP) shunt

Front 1226

Do anabolic processes generally use NAD+ or NADPH?

Back 1226

NADPH (has more letters than NADH--thus it is built up--anabolic)

Front 1227

The synthesis of steroids is a(n) _____ (catabolic/anabolic) process that uses _____ (NAD+/NADPH) to donate electrons.

Back 1227

anabolic; NADPH

Front 1228

Catabolic processes generally use _____ (NAD+/NADPH) as an electron acceptor, whereas anabolic processes generally use _____ (NAD+/NADPH) as an electron donor.

Back 1228

NAD+; NADPH

Front 1229

The synthesis of fatty acids is a(n) _____ (catabolic/anabolic) process that uses _____ (NAD+/NADPH) to donate electrons.

Back 1229

anabolic; NADPH

Front 1230

Name the three universal electron acceptors.

Back 1230

NAD+, NADP+, FAD+

Front 1231

The respiratory burst in phagocytes uses what substance as an electron carrier?

Back 1231

NADPH

Front 1232

The cytochrome P-450 system uses what substance as an electron carrier?

Back 1232

NADPH

Front 1233

In what charged state do nicotinamides and flavin nucleotides accept electrons?

Back 1233

In the NAD+, NADP+, and FAD+ forms

Front 1234

In what state do nicotinamides and flavin nucleotides donate electrons?

Back 1234

In the NADH, NADPH, and FADH2 forms; these molecules provide reducing equivalents (remember that being reduced involves more bonds to hydrogens)

Front 1235

What is the enzymatic reaction performed by hexokinase and glucokinase?

Back 1235

Both enzymes phosphorylate glucose to form glucose-6-phosphate (first step of glycolysis- and glycogen synthesis in the liver)

Front 1236

In the liver, formation of glucose-6-phosphate is the first step of which 2 reactions?

Back 1236

glycolysis and glycogen synthesis

Front 1237

Which 2 locations in the body contain high concentrations of glucokinase?

Back 1237

The liver and beta cells of the pancreas

Front 1238

True or False: Hexokinase catalyzes the same reaction as glucokinase, but it is found throughout the body rather than localized primarily to the liver.

Back 1238

true

Front 1239

Which enzyme has a higher Km: glucokinase or hexokinase?

Back 1239

glucokinase (higher Km = lower affinity) --this enzyme has no feedback-inhibition loop with glucose-6-phosphate, because its job is to store excess energy after a meal

Front 1240

Which enzyme has a higher affinity for glucose: glucokinase or hexokinase?

Back 1240

hexokinase

Front 1241

Which enzyme has a higher affinity for glucose: glucokinase or hexokinase?

Back 1241

Hexokinase; this enzyme has a feedback-inhibition loop with glucose-6-phosphate, because its job is just to keep the cells supplied with energy

Front 1242

Which enzyme has a higher Vmax: glucokinase or hexokinase?

Back 1242

Glucokinase; this enzyme has no feedback-inhibition loop with glucose-6-phosphate, because its job is to store excess energy after a meal

Front 1243

Which enzyme has a greater capacity to convert glucose to glucose-6-phosphate: glucokinase or hexokinase?

Back 1243

Glucokinase; this enzyme has no feedback-inhibition loop with glucose-6-phosphate, because its job is to store excess energy after a meal

Front 1244

Which enzyme is inhibited by negative feedback from its product, glucose-6-phosphate: glucokinase or hexokinase?

Back 1244

Hexokinase; this enzyme has a feedback-inhibition loop with glucose-6-phosphate, because its job is just to keep the cells supplied with energy

Front 1245

True or False: Both glucokinase and hexokinase yield glucose-6-phosphate as a product, and both enzymes are inhibited by their product.

Back 1245

False; only hexokinase is inhibited by glucose-6-phosphate

Front 1246

True or False: Glucokinase phosphorylates excess glucose to sequester it in the liver as glucose-6-phosphate.

Back 1246

true

Front 1247

Which enzyme is induced by insulin: hexokinase or glucokinase?

Back 1247

glucokinase

Front 1248

What is the effect of glucokinase on the blood glucose level?

Back 1248

By storing excess glucose in the liver, the liver can act as a buffer to regulate the blood glucose level

Front 1249

Name the two enzymes that catalyze the reaction of glucose into glucose-6-phosphate.

Back 1249

Hexokinase and glucokinase

Front 1250

Where in the cell are the reactions that produce 2 pyruvate molecules from 1 glucose?

Back 1250

in the cytoplasm

Front 1251

What inhibits the activity of hexokinase during glycolysis?

Back 1251

Glucose-6-phosphate provides negative feedback

Front 1252

Name three compounds that decrease the activity of pyruvate dehydrogenase through negative feedback.

Back 1252

ATP, NADH, and acetyl-CoA are inhibitors of pyruvate dehydrogenase

Front 1253

In glycolysis, what enzyme catalyzes the formation of fructose-1,6 bisphosphate?

Back 1253

Phosphofructokinase-1
(rate-limiting step)

Front 1254

In glycolysis, what enzyme catalyzes the formation of fructose-1,6 bisphosphate?

Back 1254

Phosphofructokinase-1

Front 1255

In glycolysis, what enzyme catalyzes the rate-limiting step?

Back 1255

Phosphofructokinase-1

Front 1256

In glycolysis, is ATP an activator or an inhibitor of phosphofructokinase-1 (the enzyme that catalyzes the rate-limiting step in glycolysis)?

Back 1256

inhibitor

Front 1257

True or False: In glycolysis, high levels of ATP and citrate in the cell increase the activity of phosphofructokinase-1 and lead to increased flux through the glycolytic pathway.

Back 1257

False; ATP and citrate inhibit phosphofructokinase-1 since glycolysis is unnecessary in an energy-replete cell

Front 1258

Is citrate an activator or an inhibitor of the enzyme that catalyzes the rate-limiting step in glycolysis?

Back 1258

inhibitor of phosphofructokinase-1

Front 1259

In glycolysis, fructose-2,6-bisphosphate _____ (increases/decreases) the production of fructose-1,6-bisphosphate from fructose-6-phosphate.

Back 1259

increases (through increasing activity of phosphofructokinase-1)

Front 1260

In glycolysis, is adenosine monophosphate an activator or an inhibitor of phosphofructokinase-1?

Back 1260

activator (signifies low energy state)

Front 1261

In glycolysis, fructose-1,6-bisphosphate _____ (increases/decreases) the activity of pyruvate kinase.

Back 1261

increases

Front 1262

Is fructose-2,6-bisphosphate an activator or an inhibitor of the enzyme that catalyzes the rate-limiting step in glycolysis?

Back 1262

activator

Front 1263

What enzyme catalyzes the conversion of phosphoenolpyruvate to pyruvate during glycolysis?

Back 1263

Pyruvate kinase

Front 1264

True or False: In glycolysis, ATP and alanine are inhibitors of pyruvate kinase and thus decrease the production of pyruvate when found in high concentrations in a cell.

Back 1264

true

Front 1265

In glycolysis, the formation of acetyl-CoA from pyruvate is catalyzed by what enzyme?

Back 1265

pyruvate dehydrogenase

Front 1266

True or False: In glycolysis, the reaction catalyzed by hexokinase is reversible.

Back 1266

False; this reaction is nonreversible

Front 1267

True or False: In glycolysis, the reaction catalyzed by glucokinase is reversible.

Back 1267

False; this reaction is nonreversible

Front 1268

True or False: In glycolysis, the reaction catalyzed by pyruvate kinase is reversible.

Back 1268

False; this reaction is nonreversible

Front 1269

True or False: In glycolysis, the reaction catalyzed by pyruvate dehydrogenase is reversible.

Back 1269

False; this reaction is nonreversible

Front 1270

True or False: Hexokinase is found mainly in the liver.

Back 1270

False; hexokinase is widely distributed in the body

Front 1271

In the reaction that produces glucose-6-phosphate from D-glucose, is ATP produced or required?

Back 1271

required (extra phosphate added--look at the names)

Front 1272

In the reaction that produces fructose-1,6-bisphosphate from fructose-6-phosphate, is ATP produced or required?

Back 1272

required (extra phosphate added--look at the names)

Front 1273

In the reaction that produces 3-phosphoglycerate from 1,3-bisphosphoglycerate, is ATP produced or required?

Back 1273

produced (phosphate lost--look at the names)

Front 1274

In the reaction that produces pyruvate from phosphoenolpyruvate, is ATP produced or required?

Back 1274

produced (an ATP is lost-- look at the names)

Front 1275

In glycolysis, the formation of 3-phosphoglycerate from 1,3-bisphosphoglycerate is catalyzed by which enzyme?

Back 1275

Phosphoglycerate kinase

Front 1276

True of False: In glycolysis, the reaction catalyzed by phosphoglycerate kinase is reversible.

Back 1276

true

Front 1277

What is the most potent activator of phosphofructokinase-1?

Back 1277

Fructose-2,6-bisphosphate

Front 1278

The enzyme phosphofructokinase 2 catalyzes which reaction?

Back 1278

The conversion of fructose-6-phosphate to fructose-2,6-bisphosphate

Front 1279

What enzyme converts fructose-1,6-bisphosphate (F1,6BP) into fructose-6-phosphate during gluconeogenesis?

Back 1279

Fructose bisphosphatase-1 (FBPase-1)

Front 1280

What enzyme creates fructose-2,6-bisphosphate from fructose-6-phosphate?

Back 1280

Phosphofructokinase-2 (PFK-2)

Front 1281

Fructose bisphosphatase-2 catalyzes which reaction?

Back 1281

Conversion of fructose-2,6-bisphosphate into fructose-6-phosphate

Front 1282

What function do FBP-1 and FBP-2 have in common?

Back 1282

Both remove a phosphate group from their target; FBP-1 removes that from the 1 carbon of F1,6BP, while FBP-2 removes that from the 2 carbon of F2,6BP

Front 1283

What function do PFK-1 and PFK-2 have in common?

Back 1283

Both add a phosphate group to either the 1 carbon (in PFK-1) or the 2 carbon (in PFK-2) of fructose-6-phosphate

Front 1284

True or False: In glycolysis, ATP and alanine are inhibitors of pyruvate kinase and thus decrease the production of pyruvate when found in high concentrations in a cell.

Back 1284

true

Front 1285

In glycolysis, the formation of acetyl-CoA from pyruvate is catalyzed by what enzyme?

Back 1285

pyruvate dehydrogenase

Front 1286

True or False: In glycolysis, the reaction catalyzed by hexokinase is reversible.

Back 1286

False; this reaction is nonreversible

Front 1287

True or False: In glycolysis, the reaction catalyzed by glucokinase is reversible.

Back 1287

False; this reaction is nonreversible

Front 1288

True or False: In glycolysis, the reaction catalyzed by pyruvate kinase is reversible.

Back 1288

False; this reaction is nonreversible

Front 1289

True or False: In glycolysis, the reaction catalyzed by pyruvate dehydrogenase is reversible.

Back 1289

False; this reaction is nonreversible

Front 1290

True or False: Hexokinase is found mainly in the liver.

Back 1290

False; hexokinase is widely distributed in the body

Front 1291

In the reaction that produces glucose-6-phosphate from D-glucose, is ATP produced or required?

Back 1291

required (extra phosphate added--look at the names)

Front 1292

In the reaction that produces fructose-1,6-bisphosphate from fructose-6-phosphate, is ATP produced or required?

Back 1292

required (extra phosphate added--look at the names)

Front 1293

In the reaction that produces 3-phosphoglycerate from 1,3-bisphosphoglycerate, is ATP produced or required?

Back 1293

produced (phosphate lost--look at the names)

Front 1294

In the reaction that produces pyruvate from phosphoenolpyruvate, is ATP produced or required?

Back 1294

produced (an ATP is lost-- look at the names)

Front 1295

In glycolysis, the formation of 3-phosphoglycerate from 1,3-bisphosphoglycerate is catalyzed by which enzyme?

Back 1295

Phosphoglycerate kinase

Front 1296

True of False: In glycolysis, the reaction catalyzed by phosphoglycerate kinase is reversible.

Back 1296

true

Front 1297

What is the most potent activator of phosphofructokinase-1?

Back 1297

Fructose-2,6-bisphosphate

Front 1298

The enzyme phosphofructokinase 2 catalyzes which reaction?

Back 1298

The conversion of fructose-6-phosphate to fructose-2,6-bisphosphate

Front 1299

What enzyme converts fructose-1,6-bisphosphate (F1,6BP) into fructose-6-phosphate during gluconeogenesis?

Back 1299

Fructose bisphosphatase-1 (FBPase-1)

Front 1300

What enzyme creates fructose-2,6-bisphosphate from fructose-6-phosphate?

Back 1300

Phosphofructokinase-2 (PFK-2)

Front 1301

Fructose bisphosphatase-2 catalyzes which reaction?

Back 1301

Conversion of fructose-2,6-bisphosphate into fructose-6-phosphate

Front 1302

What function do FBP-1 and FBP-2 have in common?

Back 1302

Both remove a phosphate group from their target; FBP-1 removes that from the 1 carbon of F1,6BP, while FBP-2 removes that from the 2 carbon of F2,6BP

Front 1303

What function do PFK-1 and PFK-2 have in common?

Back 1303

Both add a phosphate group to either the 1 carbon (in PFK-1) or the 2 carbon (in PFK-2) of fructose-6-phosphate

Front 1304

Which enzyme regulating the level of F2,6BP is active in the fed state?

Back 1304

Phosphofructokinase 2, increasing glycolysis and thus ATP creation for anabolic processes

Front 1305

Which enzyme regulating the level of F2,6BP is active in the fasting state?

Back 1305

Fructose bisphosphatase-2, increasing gluconeogenesis when glucose is needed for catabolic processes

Front 1306

A potent regulator of glycolysis, this compound activates the enzyme phosphofructokinase to produce fructose-1,6-bisphosphate.

Back 1306

Fructose-2,6-bisphosphate

Front 1307

A potent regulator of gluconeogenesis, this compound is converted to fructose-6-phosphate by the enzyme fructose bisphosphatase 2.

Back 1307

Fructose-2,6-bisphosphate

Front 1308

True or False: Fructose-2,6-bisphosphate is a potent regulator of both glycolysis and gluconeogenesis.

Back 1308

true

Front 1309

What will the activity level of PFK-1 be if it is in the presence of both F2,6BP, an activator, and citrate and ATP, two inhibitors?

Back 1309

It will actively convert F6P to F1,6BP because F2,6BP overrides any inhibition

Front 1310

In the fed state, does the cell perform glycolysis or gluconeogenesis? What enzyme is responsible?

Back 1310

glycolysis (When glucose is available, the body will perform glycolysis because PFK-2 is active and will increase the amount of F2,6BP)

Front 1311

In the fasting state, does the cell perform glycolysis or gluconeogenesis? What enzyme is responsible?

Back 1311

gluconeogenesis (The liver cell will perform gluconeogenesis because FBPase-2 is active and will decrease the amount of F2,6BP)

Front 1312

A patient with a genetic mutation in their glycolysis pathway is anemic; what is the likely etiology?

Back 1312

This is likely hemolytic anemia due to RBC swelling and lysis (no ATP to maintain Na+/K+ ATPase pump)-- sodium enters and stays inside-- water follows

Front 1313

What type of anemia is seen with decreased activity of erythrocyte Na+/K+ ATPase?

Back 1313

Hemolytic anemia

Front 1314

Why does inhibition of the erythrocyte Na+/K+ ATPase cause hemolytic anemia?

Back 1314

Inability to transfer ions results in cell swelling and lysis (sodium is trapped inside and water follows)

Front 1315

True or False: RBCs have mitochondria.

Back 1315

False; there are no mitochondria present in RBCs- thus they rely solely on glycolysis for energy

Front 1316

True or False: RBCs are able to metabolize glucose through oxidative phosphorylation.

Back 1316

False; RBCs have no mitochondria, which are the site of oxidative phosphorylation

Front 1317

True or False: RBCs depend solely on glycolysis to produce ATP from glucose.

Back 1317

true

Front 1318

True or False: 95% of glycolytic enzyme deficiencies are due to deficiencies specifically in pyruvate kinase.

Back 1318

true

Front 1319

True or False: 95% of glycolytic enzyme deficiencies are due to deficiencies specifically in phosphoglucose isomerase.

Back 1319

False; 4% of glycolytic enzyme deficiencies are due to deficiencies in phosphoglucose isomerase while 95% are due to deficiencies in pyruvate kinase

Front 1320

Name the most common glycolytic enzyme deficiency that leads to hemolytic anemia.

Back 1320

pyruvate kinase (this leads to continuous hemolytic anemia-- vs G6PD deficiency which is episodic with oxidative stress)

Front 1321

How many enzymes make up the pyruvate dehydrogenase complex?

Back 1321

Three

Front 1322

How many cofactors are required for pyruvate dehydrogenase complex activity?

Back 1322

Five

Front 1323

What is another name for vitamin B1?

Back 1323

Thiamine

Front 1324

Vitamin B1 is used as a cofactor in the pyruvate dehydrogenase complex as part of what compound?

Back 1324

Thiamine pyrophosphate

Front 1325

What is another name for vitamin B2?

Back 1325

Riboflavin

Front 1326

Vitamin B2 is used as a cofactor in the pyruvate dehydrogenase complex as part of what compound?

Back 1326

FAD+

Front 1327

What is another name for vitamin B3?

Back 1327

Niacin

Front 1328

What reaction is mediated by the α-ketoglutarate complex?

Back 1328

α-Ketoglutarate to succinyl-CoA in the TCA cycle

Front 1329

Vitamin B3 is used as a cofactor in the pyruvate dehydrogenase complex as part of what compound?

Back 1329

NAD+

Front 1330

What poison inhibits the function of the pyruvate dehydrogenase complex?

Back 1330

Arsenic

Front 1331

What is another name for vitamin B5?

Back 1331

Pantothenate

Front 1332

A sick patient has rice water stools, vomiting, and garlic breath; what is the diagnosis?

Back 1332

Arsenic poisoning

Front 1333

Vitamin B5 is used as a cofactor in the pyruvate dehydrogenase complex as part of what compound?

Back 1333

CoA

Front 1334

How does arsenic interfere with pyruvate dehydrogenase?

Back 1334

Arsenic inhibits lipoic acid

Front 1335

What enzyme catalyzes the conversion of pyruvate to acetyl-CoA?

Back 1335

Pyruvate dehydrogenase complex

Front 1336

Which cofactors are required for the activity of the pyruvate dehydrogenase complex?

Back 1336

B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenate), and lipoic acid

Front 1337

True or False: Pyruvate dehydrogenase complex is activated by the depletion of cell energy stores (eg, as occurs with exercise).

Back 1337

True

Front 1338

A(n) _____ (increase/decrease) in the NAD+/NADH ratio in a cell leads to increased activity of the pyruvate dehydrogenase complex.

Back 1338

Increase

Front 1339

A(n) _____ (increase/decrease) in the concentration of calcium in a cell leads to increased activity of the pyruvate dehydrogenase complex.

Back 1339

Increase

Front 1340

A(n) _____ (increase/decrease) in adenosine diphosphate in a cell leads to increased activity of the pyruvate dehydrogenase complex.

Back 1340

Increase

Front 1341

What enzyme in the citric acid cycle has a similar structure to the pyruvate dehydrogenase complex and uses the same cofactors?

Back 1341

The α-ketoglutarate dehydrogenase complex

Front 1342

Oxidative phosphorylation occurs in the _____ (mitochondria/cytoplasm).

Back 1342

mitochondria

Front 1343

What would an arterial blood gas show in pyruvate dehydrogenase deficiency?

Back 1343

Metabolic acidosis

Front 1344

What substance creates the metabolic acidosis in pyruvate dehydrogenase deficiency?

Back 1344

Patients have a lactic acidosis

Front 1345

Why is pyruvate dehydrogenase deficiency seen in alcoholics?

Back 1345

These individuals have a vitamin B1 deficiency, which is necessary to create active pyruvate dehydrogenase

Front 1346

True or False: A lack of active pyruvate dehydrogenase leads to the accumulation of pyruvate and alanine.

Back 1346

true

Front 1347

True or False: An alcoholic with decreased activity of the enzyme pyruvate dehydrogenase will have a normal neurological examination.

Back 1347

False; these individuals have neurologic deficits

Front 1348

A patient with pyruvate dehydrogenase deficiency should be given a diet high in _____ (ketogenic/glucogenic) amino acids.

Back 1348

ketogenic

Front 1349

What are the only two purely ketogenic amino acids?

Back 1349

lysine and leucine

Front 1350

In pyruvate metabolism, which enzyme catalyzes the conversion of pyruvate to alanine?

Back 1350

Alanine transaminase (ALT)

Front 1351

In pyruvate metabolism, which enzyme converts pyruvate to lactate?

Back 1351

Lactate dehydrogenase (LDH)

Front 1352

What enzyme converts pyruvate to acetyl-CoA?

Back 1352

pyruvate dehydrogenase complex (PDH)

Front 1353

In pyruvate metabolism, which enzyme catalyzes the conversion of pyruvate to oxaloacetate?

Back 1353

pyruvate carboxylase (PC)

Front 1354

Which amino acid serves as a carrier of amino groups from muscle to liver?

Back 1354

alanine

Front 1355

What are four compounds that can be formed from pyruvate?

Back 1355

Acetyl-CoA, lactate, alanine, and oxaloacetate

Front 1356

The conversion of pyruvate to lactate is the final step of which pathway?

Back 1356

Anaerobic glycolysis

Front 1357

Which cells in the body use anaerobic glycolysis as a major source of ATP?

Back 1357

RBCs, leukocytes, kidney medulla, testes, cornea and lens

Front 1358

Pyruvate can be converted to what substance used to replenish intermediates during the citric acid cycle?

Back 1358

Oxaloacetate; can also be used for gluconeogenesis

Front 1359

Pyruvate is converted into which two molecules that can enter the TCA cycle?

Back 1359

Acetyl-CoA and oxaloacetate

Front 1360

True or False: The Cori cycle transfers the metabolic burden of gluconeogenesis from RBCs and muscle to the liver.

Back 1360

true

Front 1361

What is the net gain or loss of ATP molecules during the Cori cycle?

Back 1361

There is a net loss of 4 ATP molecules

Front 1362

How many NADH molecules are produced during one turn of the citric acid cycle?

Back 1362

three

Front 1363

How many FADH2 molecules are produced during one turn of the citric acid cycle?

Back 1363

one

Front 1364

How many carbon dioxide molecules are produced during one turn of the citric acid cycle?

Back 1364

two

Front 1365

How many guanosine triphosphate molecules are produced during one turn of the citric acid cycle?

Back 1365

one

Front 1366

How many ATP molecules are produced during one turn of the citric acid cycle?

Back 1366

12 (3 * 3NADH + 1 * 2FADH2 + 1 GTP)

Front 1367

In the citric acid cycle, ATP _____ (activates/inhibits) citrate synthase.

Back 1367

inhibits

Front 1368

How many ATPs are produced from one acetyl-CoA molecule by the citric acid cycle?

Back 1368

12

Front 1369

In the citric acid cycle, ATP is an _____ (activator/inhibitor) of isocitrate dehydrogenase, whereas ADP is an _____ (activator/inhibitor).

Back 1369

inhibitor; activator (high vs low energy states)

Front 1370

How many ATP molecules are produced from one molecule of glucose by the citric acid cycle?

Back 1370

24

Front 1371

How many NADH molecules are produced from one molecule of glucose by the citric acid cycle?

Back 1371

6

Front 1372

How many FADH2 molecules are produced from one molecule of glucose by the citric acid cycle?

Back 1372

2

Front 1373

How many carbon dioxide molecules are produced from one molecule of glucose by the citric acid cycle?

Back 1373

4

Front 1374

How many guanosine triphosphate molecules are produced from one molecule of glucose by the citric acid cycle?

Back 1374

2

Front 1375

What enzyme of the citric acid cycle requires the same cofactors as pyruvate dehydrogenase complex?

Back 1375

The α-ketoglutarate dehydrogenase complex

Front 1376

The α-keoglutarate dehydrogenase complex requires which cofactors?

Back 1376

Pyrophosphate (B1), FAD (B2), NAD (B3), CoA (B5), and lipoic acid

Front 1377

In the citric acid cycle, α-ketoglutarate dehydrogenase is _____ (inhibited/activated) by the high-energy compounds NADH and ATP.

Back 1377

inhibited

Front 1378

In the citric acid cycle, ATP, acetyl-CoA, and NADH are _____ (inhibitors/activators) of pyruvate dehydrogenase.

Back 1378

inhibitors

Front 1379

What product provides negative feedback to α-ketoglutarate dehydrogenase to inhibit its function?

Back 1379

Succinyl-CoA

Front 1380

In the citric acid cycle, the production of α-ketoglutarate, succinyl-CoA, and oxaloacetate from their respective precursors produces what high-energy molecule?

Back 1380

NADH

Front 1381

Where in the cell does the TCA cycle take place?

Back 1381

The mitochondria

Front 1382

In the citric acid cycle, high-energy compounds such as ATP and NADH _____ (inhibit/activate) isocitrate dehydrogenase.

Back 1382

inhibit (isocitrate dehydrogenase is the rate limiting enzyme of the krebs/TCA cycle)

Front 1383

In the citric acid cycle, the reaction of pyruvate into acetyl-CoA is catalyzed by what enzyme?

Back 1383

Pyruvate dehydrogenase complex

Front 1384

What are the 5 cofactors required by the pyruvate dehydrogenase complex?

Back 1384

Vitamins B1 (thiamine for thiamine pyrophosphate -TPP), B2 (riboflavin for FADH2), B3 (niacin for NADH), and B5 (for CoA) and lipoic acid

Front 1385

In the citric acid cycle, the conversion of oxaloacetate to citrate is catalyzed by what enzyme?

Back 1385

citrate synthase

Front 1386

In the citric acid cycle, the conversion of isocitrate to α-ketoglutarate is catalyzed by what enzyme?

Back 1386

Isocitrate dehydrogenase

Front 1387

In the citric acid cycle, which enzyme catalyzes the conversion of α-ketoglutarate to succinyl-CoA?

Back 1387

The α-ketoglutarate dehydrogenase complex

Front 1388

Name the intermediates of the citric acid cycle.

Back 1388

Citrate, Isocitrate, α-Ketoglutarate, Succinyl-CoA, Succinate, Fumarate, Malate, and Oxaloacetate (mnemonic: Citrate Is Kreb's Starting Substrate For Making Oxaloacetate)

Front 1389

The formation what two substances during the citric acid cycle involve the release of carbon dioxide?

Back 1389

alpha-Ketoglutarate and succinyl-CoA

Front 1390

What step of the citric acid cycle produces guanosine triphosphate?

Back 1390

The conversion of succinyl-CoA into succinate

Front 1391

What step of the citric acid cycle produces FADH2?

Back 1391

The conversion of succinate into fumarate

Front 1392

True or False: The enzymes of the citric acid cycle are generally inhibited by high-energy compounds such as ATP or NADH.

Back 1392

true- feedback inhibition

Front 1393

True or False: The enzymes of the citric acid cycle are generally inhibited by low-energy compounds like adenosine diphosphate.

Back 1393

False; ADP is an activator

Front 1394

Name four enzymes in the TCA cycle whose actions are irreversible.

Back 1394

Pyruvate dehydrogenase, citrate synthase, isocitrate dehydrogenase, and α-ketoglutarate dehydrogenase

Front 1395

Electrons carried by NADH from glycolysis may enter the mitochondria via which two shuttles?

Back 1395

Malate-aspartate shuttle or glycerol-3-phosphate shuttle

Front 1396

How many ATP molecules can be produced from one NADH molecule during oxidative phosphorylation?

Back 1396

Three

Front 1397

How many ATP molecules can be produced from one FADH2 molecule during oxidative phosphorylation?

Back 1397

two

Front 1398

Which complex in the electron transfer chain receives electrons carried by NADH?

Back 1398

Complex I

Front 1399

Which complex in the electron transfer chain receives electrons carried by FADH2?

Back 1399

Complex II (succinate dehydrogenase)

Front 1400

Why does FADH2 produce fewer molecules of ATP than NADH?

Back 1400

It enters the electron transport chain at a lower energy level than NADH on complex II

Front 1401

True or False: The electron transport chain creates an electron gradient which drives production of ATP.

Back 1401

False; the electron transport chain creates a proton gradient, and this is used to form ATP

Front 1402

What interacts with complex IV of the electron transport chain to drive oxidative phosphorylation forward?

Back 1402

An oxygen molecule acts as the final electron acceptor in oxidative phosphorylation

Front 1403

What is the mechanism of action by which oligomycin interrupts ATP production?

Back 1403

Oligomycin directly inhibits mitochondrial ATPase

Front 1404

How does the pesticide rotenone block ATP synthesis?

Back 1404

Via direct inhibition of electron transport

Front 1405

What happens to the proton gradient in the mitochondria when ATPase is inhibited by oligomycin?

Back 1405

It increases, but protons cannot be released, causing the electron transport chain to halt and decreased ATP formation

Front 1406

How does the drug antimycin A block ATP synthesis?

Back 1406

Via direct inhibition of electron transport

Front 1407

How does the poison cyanide block ATP synthesis?

Back 1407

Via direct inhibition of electron transport

Front 1408

How does the gas carbon monoxide block ATP synthesis?

Back 1408

Via direct inhibition of electron transport

Front 1409

Poisons that directly inhibit the electron transport chain lead to a(n) _____ (increased/decreased) proton gradient in the mitochondria.

Back 1409

decreased

Front 1410

what is the 5 year mortality rate of CHF

Back 1410

50%

Front 1411

How do rotenone, antimycin A, cyanide, and carbon monoxide all block oxidative phosphorylation, thus decreasing ATP synthesis?

Back 1411

They are direct inhibitors of electron transport through the electron transport chain

Front 1412

Regarding oxidative phosphorylation, name three examples of uncoupling agents that will block ATP production?

Back 1412

2,4 DNP (dinitrophenol), aspirin, thermogenin

Front 1413

True or False: Regarding oxidative phosphorylation, 2,4-dinitrophenol leads to decreased ATP synthesis, because it decreases the mitochondrial proton gradient.

Back 1413

true- via uncoupling

Front 1414

Regarding oxidative phosphorylation, direct ATPase inhibitors like oligomycin _____ (increase/decrease) the proton gradient.

Back 1414

increase

Front 1415

Regarding oxidative phosphorylation, the administration of 2,4-dinitrophenol leads to the _____ (cessation/continuation) of electron transport but the _____ (cessation/continuation) of ATP production.

Back 1415

continuation; cessation

Front 1416

Regarding oxidative phosphorylation, 2,4-dinitrophenol _____ (increases/decreases) oxygen consumption.

Back 1416

increases

Front 1417

Regarding oxidative phosphorylation, 2,4-dinitrophenylhydrazine _____ (increases/decreases) the permeability of the mitochondrial membrane.

Back 1417

increases

Front 1418

Regarding oxidative phosphorylation, electron transport inhibitors _____ (increase/decrease) the proton gradient.

Back 1418

decrease

Front 1419

Regarding oxidative phosphorylation, 2,4-dinitrophenol _____ (increases/decreases) the proton gradient.

Back 1419

decreases-- it is an uncoupler

Front 1420

When acting as an uncoupling agent, aspirin _____ (increases/decreases) the proton gradient in the mitochondria.

Back 1420

decreases

Front 1421

Thermogenin in brown fat _____ (increases/decreases) oxygen consumption during oxidative phosphorylation.

Back 1421

increases-- uncoupler

Front 1422

What is the action of an uncoupling agent on the mitochondrial membrane?

Back 1422

These increase the permeability of the membrane, decreasing the proton gradient

Front 1423

Why does ATP production decrease when the mitochondrial membrane is disturbed?

Back 1423

The loss of the proton gradient means that there is nothing to drive the ATPase reaction

Front 1424

Does disruption of the proton gradient by an uncoupling agent cause electron transport to stop?

Back 1424

No; electron transport continues, but the protons moved across the membrane are free to return down the gradient without producing ATP

Front 1425

What is the result of an uncoupling agent on mitochondrial oxygen consumption?

Back 1425

There is increased oxygen consumption, because electron transport continues in an attempt to maintain the proton gradient

Front 1426

Name two mechanisms where ATP synthesis is inhibited and there is a decreased proton gradient across the inner mitochondrial membrane.

Back 1426

This occurs with electron transport inhibitors and uncoupling agents

Front 1427

To produce ATP, protons must flow down their gradient from the _____ _____ across the inner mitochondrial membrane to the _____ _____.

Back 1427

Intermembranous space; mitochondrial matrix

Front 1428

Name two mechanisms in which oxidative phosphorylation is inhibited and electron transport stops.

Back 1428

This occurs with electron transport inhibitors and ATPase inhibitors

Front 1429

In gluconeogenesis, what reaction is catalyzed by pyruvate carboxylase?

Back 1429

The conversion of pyruvate into oxaloacetate

Front 1430

In gluconeogenesis, is pyruvate carboxylase found in the mitochondria or in the cytosol?

Back 1430

The mitochondria

Front 1431

_____ (Gluconeognesis/Glycolysis) requires the catalyzation of pyruvate to oxaloacetate by pyruvate carboxylase.

Back 1431

gluconeogenesis

Front 1432

In gluconeogenesis, is phosphoenolpyruvate carboxykinase found in the mitochondria or in the cytosol?

Back 1432

The cytosol

Front 1433

In gluconeogenesis, what enzyme catalyzes the conversion of oxaloacetate into phosphoenolpyruvate?

Back 1433

Phosphoenolpyruvate carboxykinase
(PEP carboxykinase)

Front 1434

In gluconeogenesis, is fructose-1,6-bisphosphatase found in the mitochondria or in the cytosol?

Back 1434

The cytosol

Front 1435

In gluconeogenesis, what is the name of the enzyme that catalyzes the reaction of fructose-1,6-bisphosphate to fructose-6-phosphate?

Back 1435

Fructose-1,6-bisphosphatase

Front 1436

In gluconeogenesis, is glucose-6-phosphatase found in the mitochondria or in the cytosol?

Back 1436

The cytosol

Front 1437

In gluconeogenesis, does phosphoenolpyruvate carboxykinase require ATP or GTP for activity?

Back 1437

GTP

Front 1438

True or False: Gluconeogenesis occurs in skeletal muscle.

Back 1438

False; muscle does not contain the enzymes needed for gluconeogenesis

Front 1439

_____ (Odd/Even)-chain fatty acids yield propionyl-CoA during metabolism, which can produce new glucose; while _____ (odd/even)-chain fatty acids yield acetyl-CoA equivalents.

Back 1439

odd chain; even chain (acetyl CoA cannot go onto to form glucose)

Front 1440

In gluconeogenesis, what reaction is catalyzed by glucose-6-phosphatase?

Back 1440

The conversion of glucose-6-phosphate into glucose

Front 1441

True or False: The irreversible enzymes of gluconeogenesis are found only in the liver, the kidney, and the intestinal epithelium.

Back 1441

true

Front 1442

A deficiency of the key gluconeogenic enzymes that catalyze irreversible reactions leads to what condition?

Back 1442

hypoglycemia

Front 1443

_____ (Odd/Even) -chain fatty acids yield propionyl-CoA during metabolism, which can enter the citric acid cycle, undergo gluconeogensis, and serve as a glucose source.

Back 1443

odd

Front 1444

Which cofactors are required by the enzyme pyruvate carboxylase?

Back 1444

Biotin and ATP

Front 1445

Glucose-6-phosphatase is found in which cellular organelle?

Back 1445

The endoplasmic reticulum

Front 1446

Name four enzymes in gluconeogenesis whose actions are irreversible.

Back 1446

Pyruvate carboxylase, PEP carboxykinase, Fructose-1,6-bisphosphatase, Glucose-6-phosphatase (remember: Pathway Produces Fresh Glucose)

Front 1447

What is an expected presenting symptom of von Gierke's disease, which is a deficiency of glucose-6-phosphatase in the liver?

Back 1447

Severe hypoglycemia due to the lack of gluconeogenesis

Front 1448

What is the primary location of gluconeogenesis in the body?

Back 1448

liver

Front 1449

Which small molecule can produce glucose after fatty acid metabolism: acetyl-CoA or propionyl-CoA?

Back 1449

propionyl-CoA--enters TCA cycle as succinyl CoA

Front 1450

What product of the pentose phosphate pathway (HMP shunt) facilitates steroid and fatty acid synthesis?

Back 1450

NADPH

Front 1451

What is the function of NADPH in the erythrocyte?

Back 1451

It reduces glutathione-which deals with oxidative stress from H2O2

Front 1452

What are the two phases of the HMP shunt (pentose phosphate pathway)?

Back 1452

There is an initial oxidative phase and a second nonoxidative phase

Front 1453

What key enzyme regulates the oxidative phase of the HMP shunt?

Back 1453

Glucose-6-phosphate dehydrogenase

Front 1454

What vitamin is required for the nonoxidative phase of the HMP shunt?

Back 1454

The transketolases that catalyze the nonoxidative reactions require thiamine (vitamin B1) as a cofactor

Front 1455

What four products are formed after both phases of the HMP shunt?

Back 1455

Ribose-5-phosphate, G3P, F6P, and NADPH are the products

Front 1456

Which product of the HMP shunt is then used in nucleotide synthesis?

Back 1456

Ribose-5-phosphate

Front 1457

How are G3P and F6P utilized in the cell following the HMP shunt?

Back 1457

These are glycolytic intermediates and can enter glycolysis

Front 1458

The oxidative phase of the HMP shunt is _____ (reversible/irreversible), while the nonoxidative phase is ______. (reversible/irreversible).

Back 1458

Irreversible; reversible

Front 1459

Name three sites of fatty acid or steroid synthesis that would show high pentose phosphate pathway (HMP shunt) activity.

Back 1459

Lactating mammary glands, liver, adrenal cortex

Front 1460

Do the reactions of the hexose monophosphate shunt (pentose phosphate pathway) take place in the mitochondria or the cytosol of a cell?

Back 1460

cytosol

Front 1461

True or False: The hexose monophosphate shunt (pentose phosphate pathway) neither consumes nor produces ATP.

Back 1461

true

Front 1462

Where would you find elevated activity of the pentose phosphate pathway, but no fatty acid or steroid synthesis?

Back 1462

In the RBC, to reduce glutathione; remember, the RBC has no organelles

Front 1463

Name two cells that utilize NADPH for an oxidative burst.

Back 1463

Neutrophils, macrophages

Front 1464

Why would you expect cells like neutrophils and macrophages to have high concentrations of NADPH oxidase?

Back 1464

This is important for the innate immune response, rapidly releasing reactive oxygen species

Front 1465

During the oxygen-dependent respiratory burst used by neutrophils to destroy bacteria, what enzyme converts hydrogen peroxide to bleach (hypochlorite) in the presence of chloride ion?

Back 1465

Myeloperoxidase, which is found in neutrophil azurophilic granules

Front 1466

During the oxygen-dependent respiratory burst that is used by neutrophils to destroy bacteria, what enzyme converts oxygen to superoxide?

Back 1466

NADPH oxidase

Front 1467

Regarding the neutrophil oxygen-dependent respiratory burst, is glutathione reduced or oxidized when converting hydrogen peroxide to water?

Back 1467

oxidized

Front 1468

What disease is caused by a deficiency of NADPH oxidase?

Back 1468

Chronic granulomatous disease

Front 1469

Regarding the neutrophil oxygen-dependent respiratory burst, which electron carrier is used to reduce glutathione after the conversion of hydrogen peroxide to water?

Back 1469

NADPH from the HMP shunt

Front 1470

During the oxygen-dependent respiratory burst that is used by neutrophils to destroy bacteria, what enzyme converts superoxide to hydrogen peroxide?

Back 1470

Superoxide dismutase

Front 1471

Which form of glutathione must be readily available in the cell to remove reactive oxygen species to prevent cell lysis?

Back 1471

The reduced form (GSH)

Front 1472

During the oxygen-dependent respiratory burst that is used by neutrophils to destroy bacteria, what enzyme converts hydrogen peroxide to water in the presence of glutathione?

Back 1472

catalase

Front 1473

During the oxygen-dependent respiratory burst that is used by neutrophils to destroy bacteria, which enzyme converts glutathione from its reduced state (GSH) to its oxidized state (GSSG)?

Back 1473

Glutathione peroxidase

Front 1474

What enzyme uses NADPH to replenish reduced glutathione?

Back 1474

Glutathione reductase

Front 1475

True or False: The pentose phosphate pathway shunt produces NADPH.

Back 1475

true

Front 1476

What enzyme replenishes the NADPH used to reduce glutathione?

Back 1476

Glucose-6-phosphate dehydrogenase

Front 1477

What is the end product of the oxygen-dependent respiratory burst that is used to kill extracellular bacteria in the phagolysosome?

Back 1477

Bleach (HOCl, hypochlorite)