First Aid Biochem

Front 1

what comprises the nucelosome core?

Back 1

2 of each of the positively charged H2A, H2B, H3, H4 (make the histone octamer)

Front 2

what histone connects the nucleosome core?

Back 2

histone H1

Front 3

what type of chomatin is transcriptionally active?

Back 3

euchromatin

Front 4

what precursor are de novo purines made from?

Back 4

IMP

Front 5

what precursor are de novo pyrimidines made from?

Back 5

orotate

Front 6

what is the MOA of hydroxyurea?

Back 6

inhibits ribonucleotide reductase

Front 7

what is the MOA of 6-mercaptopurine?

Back 7

blocks de novo purine synthesis

Front 8

what is the MOA of 5-fluorouracil?

Back 8

inhibits thymidylate synthase

Front 9

what is the MOA of methotrexate?

Back 9

inhibits DHF reductase

Front 10

what is the MOA of trimethoprim?

Back 10

inhibits bacterial DHF reductase

Front 11

at what base does a silent mutation often occur?

Back 11

third position of codon -- tRNA wobble position

Front 12

what is a nonsense mutation?

Back 12

change resulting in an early stop codon

Front 13

what do flouroquinolones inhibit?

Back 13

DNA gyrase (specific prokaryotic topoisomerase)

Front 14

in what direction does DNA pol III proofread?

Back 14

3' -> 5' exonuclease activity

Front 15

what is the role of DNA pol I?

Back 15

degrades RNA primer and fills in gap with DNA

Front 16

what type of DNA repair is mutated in xeroderma pigmentosum?

Back 16

nucleotide excision repair resulting in accumulation of thymidine dimers with sun exposure

Front 17

what type of DNA repair is mutated in hereditary nonpolyposis colorectal cancer?

Back 17

mismatch repair

Front 18

what is the mRNA start codon?

Back 18

AUG

Front 19

what are the mRNA stop codons?

Back 19

UGA = u go away
UAA = u are away
UAG = u are gone

Front 20

in eukaryotes, what is the role of RNA pol I, RNA pol II, and RNA pol III?

Back 20

RNA pol I makes rRNA
RNA pol II makes mRNA
RNA pol III make tRNA

Front 21

what does alpha amanitin inhibit?

Back 21

RNA pol II

Front 22

what are the 3 processing steps in order for heterogenous nuclear RNA to become mRNA?

Back 22

1. 5' cap (7-methylguanosine)
2. 3' polyadenylation tail
3. slicing out of introns

Front 23

what is the role of aminoacyl-tRNA synthetase?

Back 23

scrutinizes amino acid before and after it binds to tRNA

Front 24

contrast the role of ATP vs. GTP in protein synthesis?

Back 24

ATP used for tRNA Activation (charging)

GTP used for tRNA Gripping and Going places (translocation)

Front 25

memory device for protein synthesis

Back 25

going APE
A - accepts incoming aminoacyl tRNA
P - accomodates growing Peptide
E - holds Empty tRNA as it Exits

Front 26

give examples of permanent cell types that regenerate from stem cells

Back 26

neurons, skeletal and cardiac muscle, RBCs

Front 27

what is synthesized at the RER?

Back 27

secretory (exported) proteins

Front 28

what do free ribosomes synthesize?

Back 28

cytosolic and organellar proteins

Front 29

what is the role of the SER?

Back 29

steroid synthesis and detox of drugs and poisons

Front 30

what is I cell disease?

Back 30

failure of addition of mannose-6-phosphate to lysosomal proteins; instead of going to the lysosome they are secreted outside the cell

Front 31

what is the phenotype seen in I cell disease?

Back 31

coarse facial features, clouded corneas, restricted joint movement, high plasma levels of lysosomal enzymes

Front 32

what is chediak-higashi syndrome?

Back 32

microtuble polymerization defect resulting in decreased phagocytosis

Front 33

what is kartagener's syndrome?

Back 33

immotile cilia due to dynein arm defect - results in infertility, brochiectasis, and recurrent sinusitis

assoc. with situs inversus

Front 34

what to the collagen types I - IV make?

Back 34

be so totally cool, read books

type I = bone, skin, tendons
type II = carTWOlage
type III = reticulin
type IV = basement membrane or basal lamina

Front 35

what type of collagen is more frequently involved in ehler-danlos syndrome?

Back 35

type III

Front 36

what are 3 characteristics of ehlers-danlos syndrome?

Back 36

hyperextensible skin, hypermobile joints, tendency to bleed

Front 37

what type of collagen is abn in osteogenesis imperfecta?

Back 37

type I (autosomal dominant)

Front 38

what does osteogenesis imperfecta cause?

Back 38

brittle bones with multiple fractures

blue sclera

Front 39

what type of collagen is defective in alport's syndrome?

Back 39

type IV (X-lined recessive)

Front 40

what does alport's cause?

Back 40

nephritis and deafness

Front 41

memory device for blotting procedures

Back 41

SNoW DRoP
southern = DNA
northern = RNA
western = protein

Front 42

what are microarrays used for?

Back 42

profile gene expression levels and detect single nucleotide polymorphisms

Front 43

what is ELISA testing for?

Back 43

antigen-antibody reactivity

Front 44

what does FISH allow?

Back 44

direct visualization of genes and anomalies like microdeletions

Front 45

what is the function of RNAi?

Back 45

dsRNA is synthesized that is complimentary to the mRNA sequence of interest. when transfected into human cells, dsRNA separates and promotes degradation of target mRNA

Front 46

what type of chromosomes does karyotyping look at? what is it used for?

Back 46

metaphase chromosomes; used for detecting chromosomal imbalances

Front 47

what is the defect in achrondroplasia?

Back 47

defect of the fibroblast growth factor receptor 3

Front 48

what mutation is associated with APKD? what is an important clinical association with this disease?

Back 48

mutation of apkd1 on chromosome 16

berry aneurysms

Front 49

what condition results from deletion of the APC gene on chromosome 5?

Back 49

familial adenomatous polyposis

Front 50

what chromosome is assoc. with huntington's CAG repeat?

Back 50

chromosome 4 "hunting 4 food"

Front 51

what is an important clinical assoc. of marfans?

Back 51

dissecting aortic aneurysms

Front 52

what gene is mutated in marfan's

Back 52

fibrilllin

Front 53

what gene is assoc with MEN II and III

Back 53

ret gene

Front 54

what disease is assoc. with cafe au lait spots? what chomosome?

Back 54

neurofibromatosis type I or von recklinghausen disease

long arm of chrom 17

Front 55

8 year old pt. presents with bilateral acoustic neuromas and cataracts - what chromosome is affected?

Back 55

chromosome 22 -- neurofibromatosis type 2

Front 56

pt. presents with ash leaf spots and facial lesions with an astrocytoma - what does they have?

Back 56

tuberous sclerosis

Front 57

renal cell carcinoma may occur in the context of what disease and deletion of what gene?

Back 57

von Hippel-Lindau disease with a deletion of VHL tumor supressor gene on chromosome 3

Front 58

individual has a positive sweat test - what chromosome is affected?

Back 58

usually a deletion of Phe 508 on chromosome 7 --> causes a defect in the CFTR gene leading to cystic fibrosis

Front 59

what tx will loosen the mucous plugs in cystic fibrosis/

Back 59

n-acetylcysteine

Front 60

memory device for x-linked recessive disorders

Back 60

Be Wise, Fool's GOLD Heeds False Hope

Bruton's agammaglobulinemia, Wiskott-Aldrich, Fragile X, G6PD deficiency, Ocular albinism, Lesch-Nyhan syndrome, Duchenne's MD, Hemophilia A and B, Fabry's disease, Hunter's syndrome

Front 61

pt. presents with hypertropied calfs, and proximal muscle weakness - what gene is deleted?

Back 61

frame shift mutation leading to a deleted dystropin gene

Front 62

what is becker's muscular dystrophy?

Back 62

mutated dystropin gene (not entirely absent) --> phenotype less severe than DMD

Front 63

trinucleotide repeat in fragile X?

Back 63

CGG

Front 64

memory device for trinucleotide repeat expansion diseases

Back 64

Try hunting for my fried eggs (X)

try = trinucleotide
hunting = huntington's disease (CAG)
my = myotonic dystrophy (CTG)
fried = friedrich's ataxia (GAA)
X = fragile X (CGG)

Front 65

you are counseling the mother of a down's syndrome child. what should you tell her the child is at greater risk for later in life?

Back 65

alzheimer's disease and ALL

Front 66

what are the two most common causes of down's?

Back 66

meiotic nondisjunction followed by robertsonian translocation

Front 67

a 1 month old child displays mental retardation, rocker bottom feet, a small jaw, and clenched hands. what trisomy does he have?

Back 67

Edward's syndrome - trisomy 18

Front 68

1 month old infant has cleft palate, mental retardation, and polydactyly. what trisomy does he have?

Back 68

Patau syndrome - trisomy 13

Front 69

patient displays mental retardation, good verbal skills, cheerful disposition and seems to be very friendly with strangers. what chromosome is effected?

Back 69

microdeletion of chromosome 7 causing Williams syndrome

Front 70

22q11 deletion may result from what embyological defect?

Back 70

aberrant development of the 3rd and 4th pouches

Front 71

what does DiGeorge syndrome cause?

Back 71

CATCH-22
cleft palate, abn facies, thymic aplasia, cardiac abn, hypocalcemia secondary to no parathyroid

Front 72

infant displays a high pitched cry - what chromosome is deleted?

Back 72

cri du chat syndrome with a deletion of the short arm of chromosome 5

Front 73

what does thiamine deficiency result in?

Back 73

Wernicke-Korsakoff (confusion, opthalmoplegia, ataxia with confabulation), Dry beriberi (polyneuritis), Wet beriberi (dilated cardiomyopathy)

Front 74

what does riboflavin deficiency result in?

Back 74

cheilosis (inflammation of lips, scaling and fissures)

corneal vascularization

Front 75

what is the functin of SAM?

Back 75

methyl donor man

Front 76

where is b12 found?

Back 76

animal products

Front 77

where is folate found?

Back 77

FOLiage