Question 1

Which of the following statements best describes the role of the F1-F0 ATP synthase in oxidative phosphorylation?

Accepted Answer

It catalyzes the formation of ATP from ADP and Pi using the energy from a proton gradient.

Question 2

How many protons are required to synthesize one molecule of ATP via the F1-F0 ATP synthase, assuming there are 12 c subunits in the F0 complex?

Accepted Answer

$$4$$

Question 3

Which shuttle system yields the highest number of ATP molecules per glucose during complete oxidation, and why?

Accepted Answer

Malate-aspartate shuttle, because it allows NADH to enter the matrix and donate electrons to complex I.

Question 4

What is the net ATP yield from the complete oxidation of one glucose molecule if only the glycerol-3-phosphate shuttle is used for cytosolic NADH?

Accepted Answer

$$30$$

Question 5

Which enzyme is responsible for converting glucose-1-phosphate and UTP to UDP-glucose and pyrophosphate ($$PP_i) $$during glycogen synthesis?

Accepted Answer

UDP-glucose pyrophosphorylase

Question 6

Which of the following is a primary allosteric inhibitor of glycogen phosphorylase in the liver?

Accepted Answer

Glucose

Question 7

What is the effect of high $$[ATP]$$ and low $$[ADP]$$ and $$[AMP] on $$glycolysis, the citric acid cycle, and oxidative phosphorylation?

Accepted Answer

It reduces the flux through all three pathways.

Question 8

Which enzyme catalyzes the transfer of 6 or 7 glucose residues to form branches in glycogen?

Accepted Answer

Glycogen-branching enzyme

Question 9

Which of the following best explains why the formation of UDP-glucose from glucose-1-phosphate is metabolically irreversible?

Accepted Answer

Because the hydrolysis of pyrophosphate ($$PP_i) $$drives the reaction forward.

Question 10

Which of the following statements about the malate-aspartate shuttle is correct?

Accepted Answer

It allows cytosolic NADH to donate electrons to complex I, resulting in 2.5 ATP per electron pair.

Question 11

Which of the following is the correct sequence of events during rotational catalysis in ATP synthase?

Accepted Answer

The y subunit rotates, contacting each αβ pair, forcing them into the empty, ADP-binding, and ATP-bound conformations sequentially.

Question 12

If a mutation reduced the number of c subunits in the F0 complex from 12 to 9, how many protons would be required to synthesize one ATP?

Accepted Answer

$$3$$

Question 13

Which enzyme is responsible for removing glucose residues from the non-reducing ends of glycogen during glycogen breakdown?

Accepted Answer

Glycogen phosphorylase

Question 14

Which of the following is TRUE regarding the regulation of glycogen synthase?

Accepted Answer

The active form is dephosphorylated.

Question 15

Which shuttle system transfers reducing equivalents from cytosolic NADH to ubiquinone (Q) in the electron transport chain?

Accepted Answer

Glycerol-3-phosphate shuttle

Question 16

Which of the following best describes the role of phosphoglucomutase in glycogen metabolism?

Accepted Answer

It converts glucose-6-phosphate to glucose-1-phosphate and vice versa.

Question 17

Which of the following is a direct consequence of increased [ADP] and [Pi] in the cell?

Accepted Answer

Accelerated oxidative phosphorylation.

Question 18

Which enzyme is responsible for converting glycogen phosphorylase a to the inactive b form?

Accepted Answer

Phosphorylase a phosphatase

Oxidative Phosphorylation and Metabolic Regulation: ATP Synthesis and Glycogen Metabolism

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