Question 1

Which of the following best describes the process of substrate-level phosphorylation?

Accepted Answer

ATP is produced directly by transferring a phosphate group from a substrate molecule to ADP during a metabolic reaction.

Question 2

Which of the following is the correct summary equation for cellular respiration?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} ightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O} + 	ext{energy (ATP + heat)}$$

Question 3

During the electron transport chain (ETC), what is the primary role of oxygen?

Accepted Answer

It acts as the final electron acceptor, forming water.

Question 4

Which of the following statements about chemiosmosis is correct?

Accepted Answer

It involves the movement of protons down their electrochemical gradient through ATP synthase to generate ATP.

Question 5

Which molecule is oxidized and which is reduced in the following reaction? $$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} \rightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O}$$

Accepted Answer

Glucose is oxidized; oxygen is reduced.

Question 6

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

Accepted Answer

It acts as an electron carrier, accepting electrons during redox reactions.

Question 7

Where in the cell does the Krebs (citric acid) cycle occur?

Accepted Answer

In the mitochondrial matrix

Question 8

Which of the following processes produces the greatest number of ATP molecules per glucose during cellular respiration?

Accepted Answer

Oxidative phosphorylation (electron transport chain and chemiosmosis)

Question 9

Why is the actual ATP yield per glucose molecule in cellular respiration often less than the theoretical maximum?

Accepted Answer

Some protons leak across the mitochondrial membrane, and energy is used for other cellular processes.

Question 10

Which of the following best explains why fermentation occurs in muscle cells during intense exercise?

Accepted Answer

Oxygen is limited, so cells regenerate NAD+ by reducing pyruvate to lactate.

Question 11

Which of the following is a key difference between fermentation and cellular respiration?

Accepted Answer

Fermentation produces much less ATP per glucose than cellular respiration.

Question 12

Which of the following is NOT a metabolic intermediate in the conversion of glucose to carbon dioxide during cellular respiration?

Accepted Answer

Lactate

Question 13

A patient is unable to produce functional ATP synthase. Which process would be most directly affected?

Accepted Answer

Chemiosmosis and oxidative phosphorylation

Question 14

Which of the following correctly matches the cellular location with the process?

Accepted Answer

Glycolysis – cytoplasm

Question 15

Which of the following statements about the use of lipids as an energy source is correct?

Accepted Answer

Fatty acids are broken down by beta-oxidation to form acetyl-CoA, which enters the Krebs cycle.

Question 16

Which of the following best describes the role of the electron transport chain (ETC) in cellular respiration?

Accepted Answer

It transfers electrons from NADH and FADH2 to oxygen, pumping protons to create a gradient for ATP synthesis.

Question 17

Which of the following is a product of fermentation in yeast cells?

Accepted Answer

Ethanol

Question 18

Which of the following statements about redox reactions in cellular respiration is correct?

Accepted Answer

Glucose is oxidized to carbon dioxide, and oxygen is reduced to water.

Question 19

Which of the following best explains why proteins can be used as an energy source in cellular respiration?

Accepted Answer

Amino acids can be deaminated and their carbon skeletons enter the Krebs cycle as intermediates.

Question 20

A cell is exposed to cyanide, which blocks the transfer of electrons to oxygen in the ETC. What is the most immediate effect?

Accepted Answer

ATP production by oxidative phosphorylation stops.

Chapter 6: Harvesting Chemical Energy – Study Guide

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