Question 1

Which enzyme catalyzes the conversion of 2-phosphoglycerate to phosphoenolpyruvate (PEP) in glycolysis?

Accepted Answer

Enolase

Question 2

What is the net ATP gain from glycolysis per molecule of glucose under anaerobic conditions?

Accepted Answer

2 ATP

Question 3

Which reaction in glycolysis is considered highly exergonic and essentially irreversible?

Accepted Answer

Conversion of phosphoenolpyruvate (PEP) to pyruvate

Question 4

Given the reaction catalyzed by pyruvate kinase: $\mathrm{PEP} + \mathrm{ADP} \rightarrow \mathrm{pyruvate} + \mathrm{ATP}$, what is the standard free energy change ($\Delta G^\circ'$) for this reaction?

Accepted Answer

$\Delta G^\circ' = -31.4 \ \mathrm{kJ/mol}$

Question 5

Which of the following best explains why reactions 1, 3, and 10 are considered the major drivers of glycolysis?

Accepted Answer

They are highly exergonic and essentially irreversible.

Question 6

During glycolysis, which molecule is directly responsible for the transfer of a phosphate group to ADP to form ATP?

Accepted Answer

Phosphoenolpyruvate (PEP)

Question 7

Which of the following is a correct description of the fate of pyruvate under aerobic conditions?

Accepted Answer

It enters the mitochondria and is converted to acetyl-CoA.

Question 8

In glycolysis, the conversion of glyceraldehyde-3-phosphate (GAP) to 1,3-bisphosphoglycerate involves which of the following cofactors?

Accepted Answer

NAD+

Question 9

Which step in glycolysis is responsible for the splitting of a six-carbon sugar into two three-carbon molecules?

Accepted Answer

Cleavage of fructose-1,6-bisphosphate to glyceraldehyde-3-phosphate and dihydroxyacetone phosphate

Question 10

Which of the following statements about the enolase-catalyzed reaction in glycolysis is correct?

Accepted Answer

It converts 2-phosphoglycerate to phosphoenolpyruvate (PEP) by removing water.

Question 11

If a mutation prevents the conversion of PEP to pyruvate, which of the following would most likely occur?

Accepted Answer

Glycolysis would halt at the PEP step, and ATP yield would decrease.

Question 12

Which of the following best describes the role of ATP in the pyruvate kinase reaction?

Accepted Answer

ATP is produced from ADP and inorganic phosphate.

Question 13

Which of the following is NOT a product of the glycolytic pathway?

Accepted Answer

CO$_2$

Question 14

Which glycolytic intermediate is used in both the payoff and investment phases of glycolysis?

Accepted Answer

Glyceraldehyde-3-phosphate (GAP)

Question 15

Which of the following reactions in glycolysis is coupled to the reduction of NAD$^+$ to NADH?

Accepted Answer

Glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate

Question 16

Which of the following best explains why glycolysis is essential for red blood cells?

Accepted Answer

Red blood cells lack mitochondria and rely solely on glycolysis for ATP production.

Question 17

Which of the following is the correct chemical equation for the enolase-catalyzed reaction in glycolysis?

Accepted Answer

$\mathrm{2-phosphoglycerate} \rightarrow \mathrm{phosphoenolpyruvate} + \mathrm{H}_2\mathrm{O}$

Question 18

Which glycolytic enzyme is responsible for the final step of glycolysis, producing pyruvate?

Accepted Answer

Pyruvate kinase

Question 19

Which of the following statements about the conversion of DHAP to GAP in glycolysis is correct?

Accepted Answer

It is catalyzed by triose phosphate isomerase.

Question 20

Which of the following best describes the role of glycolysis in cellular metabolism?

Accepted Answer

It is the primary pathway for the breakdown of glucose to generate ATP.

Glycolysis: Key Steps and Energetics

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