Question 1

Which of the following best describes the role of NAD+ in cellular respiration?

Accepted Answer

NAD+ functions as an electron carrier, accepting electrons during glycolysis and the citric acid cycle.

Question 2

During glycolysis, what is the net yield of ATP and NADH per molecule of glucose?

Accepted Answer

$2$ ATP and $2$ NADH

Question 3

Which process directly links glycolysis to the citric acid cycle?

Accepted Answer

Pyruvate oxidation to Acetyl-CoA

Question 4

If oxygen is not present in a cell, which process will be inhibited, and what is the likely fate of pyruvate?

Accepted Answer

Citric acid cycle will be inhibited; pyruvate will be converted to lactate or ethanol.

Question 5

Which of the following equations correctly represents the overall reaction for glycolysis?

Accepted Answer

$\mathrm{Glucose} + 2\ \mathrm{NAD}^+ + 2\ \mathrm{ADP} + 2\ \mathrm{P_i} \rightarrow 2\ \mathrm{Pyruvate} + 2\ \mathrm{NADH} + 2\ \mathrm{ATP} + 2\ \mathrm{H_2O}$

Question 6

Which step in cellular respiration produces the most ATP per glucose molecule?

Accepted Answer

Oxidative phosphorylation (electron transport chain and ATP synthase)

Question 7

What is the main purpose of the electron transport chain in mitochondria?

Accepted Answer

To transfer electrons from NADH and FADH$_2$ to oxygen, creating a proton gradient for ATP synthesis

Question 8

Which of the following is TRUE about substrate-level phosphorylation?

Accepted Answer

It directly transfers a phosphate group from a substrate to ADP to form ATP.

Question 9

How many turns of the citric acid cycle are required to fully oxidize one molecule of glucose?

Accepted Answer

Two

Question 10

Which molecule acts as the final electron acceptor in aerobic cellular respiration?

Accepted Answer

O$_2$

Question 11

A patient has a genetic defect that impairs the function of ATP synthase. Which process will be most directly affected?

Accepted Answer

Production of ATP via oxidative phosphorylation

Question 12

Which of the following best explains why enzymes are necessary for cellular respiration?

Accepted Answer

Enzymes lower the activation energy, allowing reactions to occur efficiently at body temperature.

Question 13

Which of the following is NOT a product of the citric acid cycle per glucose molecule?

Accepted Answer

2 NADH

Question 14

If a cell is deprived of oxygen, which of the following will immediately decrease?

Accepted Answer

ATP production by oxidative phosphorylation

Question 15

Which of the following statements about the location of cellular respiration steps is correct?

Accepted Answer

Pyruvate oxidation and the citric acid cycle occur in the mitochondrial matrix.

Question 16

A researcher adds a chemical that blocks NADH from donating electrons to the electron transport chain. What is the most likely consequence?

Accepted Answer

The proton gradient across the inner mitochondrial membrane will decrease.

Question 17

Which of the following is the correct sequence of major steps in aerobic cellular respiration?

Accepted Answer

Glycolysis → Pyruvate Oxidation → Citric Acid Cycle → Electron Transport Chain

Question 18

Which of the following best describes oxidative phosphorylation?

Accepted Answer

ATP is produced using energy from a proton gradient created by the electron transport chain.

Question 19

A mutation causes a cell to produce a nonfunctional FAD. Which process will be most directly affected?

Accepted Answer

Citric acid cycle and electron transport chain

Question 20

Which of the following is a correct summary of the ATP yield from one glucose molecule after glycolysis and the citric acid cycle (excluding oxidative phosphorylation)?

Accepted Answer

$4$ ATP

Cellular Respiration: Core Concepts and Pathways

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