2016 biochem

Question 1

Which IF adds aa-tRNA to the P site of the ribosome?

a. IF1
b. IF2
c. IF3
d. IF4

Answer 1

b. IF2

Question 2

In a PCR 20 cycles, what is the number of products for a single DNA strand (only one primer used)?

a. 20
b. 40
c. 60
d. 80

Answer 2

a. 20

Question 3

Deficiency of Vit C and Cu will result in dysfunction in what part of collagen structure?

a. Hydroxylation and cross-linking
b. Methylation and phosphorylation

Answer 3

a. Hydroxylation and cross-linking

Question 4

What characterizes CFJ syndrome?

a. increased prion beta sheets
b. increased prion phosphorylation

Answer 4

a. increased prion beta sheets

Question 5

what stabilizes a primary protein structure?

a. Glycosyl bonds
b. S-S bonds
c. S-H bonds
d. peptide bonds

Answer 5

d. peptide bonds

Question 6

how are isozymes and enzymes related?

a. They catalyze the same reaction
b. They use the same cofactors
c. They use the same reversible inhibitors

Answer 6

a. They catalyze the same reaction

Question 7

What enzyme is involved in uric acid synthesis?

Answer 7

xanthine oxidase

Question 8

Which pair of products would be most likely produced by catabolic pathway?

a. ADP, NADH
b. ATP, NAD+
c. ATP, NADH
d. ADP, NAD+

Answer 8

c. ATP, NADH

Question 9

What is a characteristic of mRNA editing?

a. tissue-specific
b. 2 identical proteins
c. activation of phosphorylation
d. transcription regulation

Answer 9

a. tissue-specific

Question 10

What type of mutation in coagulation factor 8 causes severe hemophilia type A?

a. inversion
b. missense
c. single
d. duplication

Answer 10

a. inversion

Question 11

Farnysl and farnsyl give us what in cholesterol synthesis?

a. 5-Pyrophospho-mevalonate
b. IPP
c. Mevalonate
d. Squalene

Answer 11

d. Squalene

Question 12

What is the repair mechanism affected in hereditary nonpolyposis colon cancer?

a. Nucleotide Excision Repair
b. Base excision repair
c. Mismatch repair system

Answer 12

c. Mismatch repair system

Question 13

What’s the structure of histones in a nucleosome?

a. Octomer
b. Tetramer
c. Hexamer
d. Dimer

Answer 13

a. Octomer

Question 14

Which of these is the target of restriction endonuclease?

a. Double strand DNA
b. Single strand DNA
c. Double strand RNA
d. Single strand RNA

Answer 14

a. Double strand DNA

Question 15

Which nucleoside activates RAS protein?

a. ATP
b. CTP
c. GTP

Answer 15

c. GTP

Question 16

Which DNA polymerase has 5’ to 3’ exonuclease activity?

a. I
c. II
b. III

Answer 16

a. I

Question 17

What is the rate limiting enzyme of converting triglycerides to free fatty acid?

a. adipose triglyceride lipase (ATGL)
b. hormone sensitive lipase (HSL)
c. mono glyceride lipase (MGL)

Answer 17

b. hormone sensitive lipase (HSL)

Question 18

What activates LCAT?

a. Apo A
b. Apo B
c. Apo C
d. Apo D

Answer 18

a. Apo A

Question 19

What is the major component of lipid raft?

a. cholesterol
b. TAG

Answer 19

a. cholesterol

Question 20

What is used to make ketone bodies in prolonged (>21days) starvation?

a. Lactate from RBCs
b. fatty acid from adipose tissue
c. long chain amino acids from skeletal muscles
d. glycerol from adipose tissue

Answer 20

b. fatty acid from adipose tissue

Question 21

What is used as a cofactor for transamination reaction?

Answer 21

Pyridoxal phosphate

Question 22

Respiration ratio of isolated mitochondria was measured as the concentration of oxygen. What should be added to reduce the respiration ratio (decrease oxygen)?

a. ATP
b. NAD+
c. FAD
d. ADP

Answer 22

d. ADP

Question 23

Which of the following happens when lactate is failed to be exported from the muscles?

a. glycolysis stops in muscles
b. gluconeogenesis stops in liver
c. oxidation of lactate to pyruvate
d. fatty acid synthesis/ oxidation stops

Answer 23

a. glycolysis stops in muscles