Question 1

Which molecule is represented by label 'a' in the diagram, and what is its role in cellular respiration?

Accepted Answer

Acetyl-CoA; it delivers the acetyl group to the citric acid cycle.

Question 2

Label 'b' in the diagram represents the release of which molecule during the conversion of pyruvate to acetyl-CoA?

Accepted Answer

Carbon dioxide ($$CO_2)$$

Question 3

What is the function of NAD+ (label 'c') in the citric acid cycle?

Accepted Answer

It accepts electrons and becomes reduced to NADH.

Question 4

Which process is indicated by label 'l', and what is the main product?

Accepted Answer

Substrate-level phosphorylation; ATP

Question 5

Label 'm' shows the conversion of malate to oxaloacetate. Which coenzyme is reduced in this step?

Accepted Answer

NAD$$^+ is $$reduced to NADH

Question 6

What is the significance of the molecule represented by label 'f' (NADH) in cellular respiration?

Accepted Answer

It donates electrons to the electron transport chain, driving ATP synthesis.

Question 7

Which step in the citric acid cycle is responsible for the direct generation of GTP or ATP, as shown by label 'l'?

Accepted Answer

Conversion of succinyl-CoA to succinate

Question 8

Label 'n' represents the reduction of FAD to FADH$$_2. $$Which substrate is oxidized in this reaction?

Accepted Answer

Succinate

Question 9

If a mutation prevented the formation of NADH at label 'e', what would be the most immediate consequence for the cell?

Accepted Answer

The electron transport chain would receive fewer electrons, reducing ATP production.

Question 10

Which of the following best describes the overall function of the citric acid cycle as depicted in the diagram?

Accepted Answer

To oxidize acetyl-CoA, generating NADH and FADH$$_2$$ for use in the electron transport chain.

Cellular Respiration: Redox Reactions, Pathways, and ATP Production

Study Guide - Practice Questions