Phase A/ Biochem

Question 1

Why do mycoplasma and chlamydia stain poorly?

Answer 1

no peptidoglycan

Question 2

What mediates endotoxin activity of LPS?

Answer 2

Lipid A

Question 3

which bacteria form spores?

Answer 3

gram + only

Question 4

polyenes with broad antifungal activity

bind to membrane sterols (ergosterol) and causes membrane disruption by acting as a pore

Answer 4

amphotericin B
nystatin
Use (amphotericin B): invasive fungal infections -> Candida, Aspergillus, Cryptococcus,

Question 5

prevent ergosterol synthesis by inhibition of 14-alpha-demethylase

Answer 5

"azoles"
voriconazole
itraconazole
fluconazole
terconazole

Question 6

systemic imidazole antifungal that inhibits CYP3A4

Answer 6

ketoconazole
Many drug interactions
at high dose, inhibits adrenal steroid biosynthesis

Question 7

antifungal that disrupts mitotic spindles and is used for hair, nails and skin infections

Answer 7

Griseofulvin

Question 8

inhibits squalene epoxidase, causing decreased ergosterol and increased squalene (toxic to fungus)

Answer 8

terbinafine (Lamisil)*
buenafine
naftifine
tolnaftate (Tinactin)

Question 9

inhibits synthesis of beta(1,3)-D-glucan

Answer 9

caspofungin*
micafungin
anidulafungin

Question 10

converted to 5-FU in fungal cells and phosphorylated to 5-FdUMP to inhibit thymidylate synthase; also disrupts protein synthesis when incorporated in to RNA

Answer 10

flucytosine

Question 11

antiviral agent resistance mechanism

Answer 11

mutation in viral thymidine kinase

viral nucleoside analogs require activation by viral thymidine kinase.

Question 12

sources of acid in the blood

Answer 12

sulfuric acid -> dietary sulfate, s-containing amino acids
carbonic acid -> CO2 from TCA
lactic acid -> anaerobic glycolysis
pyruvic acid -> glycolysis
citric acid -> TCA & diet

Question 13

what cells have high levels of carbonic anhydrase?

Answer 13

RBCs

Question 14

charge of DNA

charge of histone

Answer 14

negative

positive (due to lysine & arginine)

Question 15

histone not in nucleosome core

Answer 15

H1

2A, 2B, H3, H4 all in nucleosome core

Question 16

highly condensed and transcriptionally inactive

Answer 16

heterochromatin

Question 17

transcriptionally active

Answer 17

euchromatin

Question 18

methylation here represses transcription

Answer 18

CpG islands

Question 19

location of ETC

Answer 19

inner mitochondrial membrane

The cristae increase the SA of the IMM

Question 20

purines

Answer 20

adenine

guanine

Question 21

pyrimadines

Answer 21

cytosine
uracil
thymine

Question 22

template for mRNA synthesis

Answer 22

sense strand

Question 23

smooth ER in skeletal muscle

Answer 23

sarcoplasmic reticulum

Question 24

site of lipid synthesis & is more abundant in cells which synthesize hormones

Answer 24

smooth ER

Question 25

adds carbohydrates & lipids to proteins from RER

Answer 25

Golgi apparatus

Question 26

protein structure characterized by large number of H-bonds

Answer 26

beta pleated sheet

Question 27

synthesized from thiamine chelates Mg2+ which then binds tightly to enzyme Fxn: decarboxylation of alpha keto acids and utilization of pentose phosphates in Pentose Phosphate Pathway

Answer 27

TPP | thiamine pyrophosphate

Question 28

coenzyme that bind to lysines in carboxylases

Answer 28

biotin

Question 29

from panthothenate | forms thioesters with acyl groups

Answer 29

CoASH

Question 30

from vit B6 | reactive aldehyde that forms covalent intermediate with amino groups of Schiff bases

Answer 30

pyridoxal phosphate (PLP)

Question 31

coenzyme from niacin & ATP

Answer 31

NAD+

Question 32

bind irreversibly to active site on enzyme and inhibit it

Answer 32

suicide inhibitors

Question 33

concentration of substrate to reach 1/2 Vmax

Answer 33

Km

Question 34

regulatory protein of the Ca2+ ATPase of the ER

Answer 34

calmodulin the Ca2+ ATPase is activated to pump calcium from the cytosol into the lumen of the ER when a rise in intracellular concentration causes calcium binding to calmodulin, followed by its dissociation from the transporter

Question 35

cAMP-regulated chloride channel

Answer 35

CFTR

Question 36

integral membrane receptors which recognize lysosomal enzymes in the Golgi

Answer 36

mannose 6-phosphate receptors

Question 37

B3

Answer 37

niacin | NAD+

Question 38

B2

Answer 38

riboflavin | FAD, FMN

Question 39

B1

Answer 39

thiamine | TPP

Question 40

B5

Answer 40

pantothenic acid | CoA

Question 41

B6

Answer 41

pyridoxine | PLP

Question 42

B7

Answer 42

biotin

Question 43

B9

Answer 43

folate

Question 44

B12

Answer 44

cobalamin

Question 45

vit C

Answer 45

ascorbic acid

Question 46

vitamin used to treat measles and AML (M3) antioxidant essential for normal differentiation of epithelial cells visual pigments

Answer 46

vitamin A = retinol Deficiency causes night blindness, dry, scaly skin, alopecia, keratomalacia, immune suppression. Excess: arthralgia, scaly skin, alopecia, cerebral edema, pseudotumor cerebri, osteoporosis, hepatic abnormalities; TERATOGEN

Question 47

``` cofactor for: pyruvate dehydrogenase (glycolysis -> TCA) alpha-ketoglutarate dehydrogenase (TCA) transketolase (HMP shunt) branched-chain ketoacid dehydrogenase ```

Answer 47

thiamine (B1) Dx deficiency: increased RBC transketolase activity after giving B1

Question 48

damage to medial dorsal nuclei of thalamus/mamillary bodies confusion, ataxia, confabulation, personality change permanent memory loss vitamin B1 def

Answer 48

Wernicke-Korsakoff syndrome

Question 49

causes beriberi

Answer 49

thiamine deficiency dry beriberi: polyneuritis, symmetrical muscle wasting wet beriberi: high output cardiac failure, edema

Question 50

cofactor for redox reactions (ex: succinate dehydrogenase reaction in TCA) cheilosis, corneal vascularization

Answer 50

riboflavin (B2) FAD & FMN "flav-o-flav has 2 gold teeth, smooth lips and drinks beri soda"

Question 51

Diarrhea, Dementia, Dermatitis (3 D's) | Glossitis

Answer 51

niacin (B3) | pellagra

Question 52

cofactor for acyl transfers (CoA) & fatty acid synthase

Answer 52

pantothenate (B5) | "pento"thenate

Question 53

Cofactor for carboxylase reactions

Answer 53

Biotin

Question 54

Coenzyme synthesized from niacin and ATP

Answer 54

NAD