Step 1 - Biochemistry

Front 1

Which form of chromatin is transcriptionally active?

Back 1

Euchromatin
(Eu=true, truly transcribed)

Front 2

Which form of chromatin is transcriptionally inactive?

Back 2

Heterchromatin
(HeteroChromatin=Highly Condensed)

Front 3

Which nucleotides are the purines?

Back 3

Adenine and Guanine
(PURe As Gold)

Front 4

Which nucleotides are the pyrmidines?

Back 4

Cytosine Uracil (RNA only) Thymine (DNA) only

CUT the PY

Front 5

Which H-bonds are stronger G-C or A-T?

Back 5

G-C have 3 H bonds
A-T have 2 H bonds

Front 6

Which enzyme is inhibited by hydroxyurea? What process does this interfere with?

Back 6

Ribonucleotide reductase
Nucleotide synthesis

Front 7

Which enzyme is inhibited by methotrexate?

Back 7

Dihydrofolate reductase

Front 8

Which enzyme is inhibited by trimethoprim?

Back 8

BACTERIAL dihydrofolate reductase

Front 9

What enzyme is missing in severe combined immunodeficiency disease (SCID)? Why does it cause it?

Back 9

Adenosine deaminase deficiency
Prevents DNA synthesis leading to decreased lymphocyte count

Front 10

What enzyme is missing in Lesch-Nyhan syndrome? What excess does this produce?

Back 10

Missing HGPRT
(He's Got Purine Recovery Trouble)
Excess uric acid - gout, retardation, agression, hyperuricemia

Front 11

What are the four types of DNA mutations? Rank the severity

Back 11

Silent - Base change still codes same aa
Missense - changes one amino acid
Nonsense - change leads to stop codon (Stop the Nonsense!)
Frame shift - Change leads to misreading of all nucleotides
Rank: Nonsense>Missense> Silent

Front 12

What enzyme is inhibited by fluoroquinolones? What type of enzyme is it?

Back 12

DNA gyrase
Prokaryotic topoisomerase - relieves supercoils created during replication

Front 13

What direction are RNA and DNA synthesized in?

Back 13

5' to 3'

Front 14

What type of DNA damage cannot be repaired in patients with xeroderma pigmentosum?

Back 14

Cannot repair thymidine dimers
Children get melanoma in sunlight

Front 15

What type of DNA damage cannot be repaired in patients with hereditary nonpolyposis colorectal cancer (HNPCC)?

Back 15

Mismatches cannot be repaired

Front 16

What direction are proteins synthesized in?

Back 16

N terminus to C terminus

Front 17

What enzyme is inhibited by alpha-amanitin? Where does it come from? What organ is most affected?

Back 17

Alpha-amanitin inhibits RNA polymerase II (prevents mRNA synthesis)
Comes from death cap mushrooms
Causes liver failure

Front 18

What process is inhibited by aminoglycosides?

Back 18

Inhibit formation of the initiation complex and cause misreading of mRNA

Front 19

What ribosomal subunit is inhibited by chloramphenicol?

Back 19

50S peptidyltransferase

Front 20

What ribosomal subunit is inhibited by macrolides?

Back 20

50S - block translocation

Front 21

What ribosomal subunit is blocked by clindamycin?

Back 21

50S - blocks translocation

Front 22

What phase transition is inhibited by p53 and RB?

Back 22

G1 to S progression

Front 23

What defect results in I-cell disease?

Back 23

Failure of addition of M-6P to lysosome proteins - leads to secretion out of the cell instead of into lysosomes
Causes coarse facial features, clouded cornea

Front 24

What cell structure does mebendazole/thiabendazole act on? What is it used for?

Back 24

Microtubules
Anti-helminth

Front 25

What cell structure does griseofulvin act on? What is it used for?

Back 25

Microtubules
Antifungal

Front 26

What cell structure does vincristine/vinblastine act on? What is it used for?

Back 26

Microtubules
Anti-cancer

Front 27

What cell structure does paclitaxel act on? What is it used for?

Back 27

Microtubules
Anti-breast cancer

Front 28

What cell structure does colchicine act on? What is it used for?

Back 28

Microtubules
Anti-gout

Front 29

What is the defect in Chediak Higashi syndrome? What are the clinical sequelae?

Back 29

Microtubule polymerization defect - results in decreased phagocytosis
Results in pyogenic infections, albinism, and peripheral neuropathy

Front 30

What is the defect in Kartagener's syndrome? What are the clinical sequelae?

Back 30

Dynein defect - results in immotile cilia
Results in infertility (immotile sperm), bronchiectasis, and recurrent sinusitis

Front 31

Which collagen type is normally affected in Ehlers-Danlos syndrome?

Back 31

Type III

Front 32

Which collagen type is defective in osteogenesis imperfecta? Aside from fractures what are the other signs?

Back 32

Type I
Blue sclera
Hearing loss

Front 33

Which collagen type is defective in Alport's syndrome? How is it inherited? What are the clinical sequelae?

Back 33

Type IV
X-linked recessive
Progressive hereditary nephritis and deafness

Front 34

What is the most common defect in Marfan's syndrome?

Back 34

Fibrillin

Front 35

What enzyme is commonly deficient in emphysema? What is the enzyme's function?

Back 35

Alpha-1 antitrypsin
Inhibits elastase

Front 36

Which type of blot identifies a specific DNA, RNA, or protein sequence?

Back 36

Southern - DNA
Northern - RNA
Western - Protein
(SNoW DRoP)

Front 37

What is the cause of Prader-Willi syndrome? What are the clinical sequelae?

Back 37

Deletion of a normally active paternal allele
Prader-Willi=Paternal
Mental retardation, hyperphagia, obesity, hypogonadism

Front 38

What is the cause of Angelman's syndrome? What are the clinical sequelae?

Back 38

Deletion of a normally active maternal allele
angelMan's syndrome=Maternal
Mental retardation, seizures, ataxia, inappropriate laughter

Front 39

What is the inheritance pattern of hypophosphatemic rickets (vitamin-d resistant rickets)?

Back 39

X-linked DOMINANT

Front 40

What mutation is seen in patients with achondroplasia?

Back 40

Mutation to fibroblast growth factor receptor 3

Front 41

What mutation is most commonly seen in patients with autosomal dominant polycystic kidney disease and on what chromosome is it? What kidney does it affect? Aside from kidney problems, what is the most important sequelae of the disease?

Back 41

APKD1 on chromosome 16
Bilateral involvement of kidneys
Berry aneurysms in the circle of Willis

Front 42

What gene is mutated in patients with familial adenomatous polyposis? What chromosome is it on?

Back 42

APC gene - chromosome 5

Front 43

What are common presentations of a patient with hereditary hemorrhagic telangiectasia?

Back 43

Telangiectasia - duh
Epistaxis
Skin discoloration
AVMs

Front 44

What lab value is commonly affected by hereditary spherocytosis? What is the defect? What treatment is curative?

Back 44

Increased mean corpuscular hemoglobin concentration
Defect in ankyrin or spectrin
Splenectomy is curative

Front 45

What trinucleotide repeat is seen in Huntington's? What chromosome is it on?

Back 45

CAG repeat
Chromosome 4 (Hunting 4 food)

Front 46

What neurotransmitters are commonly altered in patients with Huntington's?

Back 46

Decreased GABA and ACh

Front 47

What is a common life threat to patients with Marfan's? What is the defect?

Back 47

Dissecting aortic aneurysms
Fibrillin defect

Front 48

What gene is mutated in some patients with mutliple endocrine neoplasia?

Back 48

ret gene

Front 49

What type of gene is VHL? What is the result of its deletion? What type of neoplasia is commonly seen?

Back 49

Tumor suppressor gene
Increased expression of the transcription factor Hypoxia Inducible Factor (HIF) which promotes angiogenic growth
Many cases result in renal cell carcinoma

Front 50

Which two infections are commonly found in patients with cystic fibrosis?

Back 50

Pseudomonas
S. Aureus

Front 51

What is the genetic defect in Duchenne's muscular dystrophy (what protein and what happens to the gene)?

Back 51

Deletion of dystrophin gene

Front 52

What gene is affected by fragile X syndrome? What is the defect?

Back 52

FMR1 gene - CGG repeat
fraGile X= CGG

Front 53

What chromosome is commonly affected in Down's syndrome? What happens to it?

Back 53

Trisomy of chromosome 21

Front 54

What is each component of the quad test of pregnancy? What are the relative values of each in Down's?

Back 54

AFP - decreased
B-hCG - increased
estriol - decreased
inhibin A - increased

Front 55

Which vitamins are fat soluble? What is their important function?

Back 55

A - Vision
D - Calcium homeostasis
E - Antioxidant
K - Clotting

Front 56

Which two water soluble vitamins are stored in the liver?

Back 56

B12 and folate

Front 57

What vitamin is missing in Korsakoff's syndrome and Beriberi?

Back 57

B1 - thiamine

Front 58

Deficiency of what vitamins leads to macrocytic, megaloblastic anemia?

Back 58

B12
Folate