end exam 3

Question 1

Which enzyme is the main regulator of glycolysis

Answer 1

pfk-1

Question 2

What is the potential metabolic fate of pyruvate in a human during anaerobic activity

Answer 2

lactate

Question 3

Which reaction in glycolysis is a redox reaction

Answer 3

glyceraldehyde-3-P ➞ 1,3-bisphosphoglycerate

Question 4

Which enzyme of the citrate cycle catalyzes the oxidative decarboxylation reaction that
produces succinyl-CoA?

Answer 4

a-ketogluterate dehydrogenase

Question 5

The poison 1080 works via metabolic conversion of fluoroacetate to fluorocitrate. Which
enzyme in the citrate cycle is inhibited by this poison

Answer 5

aconitase

Question 6

The FAD cofactor of pyruvate dehydrogenase is directly responsible for

Answer 6

oxidizing the thiols on lipoamide to form a disulphide

Question 7

Redox-active copper ions are bound to

Answer 7

complex 4

Question 8

Complex II is often not included in the electron transport chain. This is because ___

Answer 8

Complex II has no effect on the proton gradient

Question 9

Briefly explain why reactions 1-5 of glycolysis are commonly referred to as the “energy-
investment phase”, while reactions 6-10 are referred to as the “energy-payoff phase

Answer 9

2 ATP are input in the first stage while 4 ATP are output in the 2nd stage

Question 10

In the Q cycle, ubiquinol (QH 2) is used as an electron donor. Give two
reasons why NADH could not be used in its place.

Answer 10

NADH is too hydrophilic to travel through the membrane
NADH can only transfer 2 electrons at a time but Cytochrome C can only take 1