Question 1

Which of the following best explains why brown fat is important for small mammals, including humans, in cold environments?

Accepted Answer

Brown fat contains more mitochondria that generate heat by uncoupling electron transport from ATP synthesis.

Question 2

Which of the following statements about the relationship between breathing and cellular respiration is correct?

Accepted Answer

Breathing supplies oxygen for cellular respiration and removes carbon dioxide produced by cellular respiration.

Question 3

What is the overall chemical equation for cellular respiration?

Accepted Answer

$$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O + ATP$$

Question 4

During which stage of cellular respiration is the majority of ATP produced?

Accepted Answer

Oxidative phosphorylation

Question 5

Which of the following best describes the role of oxygen in cellular respiration?

Accepted Answer

Oxygen is the final electron acceptor in the electron transport chain, forming water.

Question 6

If a poison blocks the flow of electrons along the electron transport chain, which of the following will immediately stop?

Accepted Answer

ATP synthesis by oxidative phosphorylation

Question 7

Which of the following is a net product of glycolysis per molecule of glucose?

Accepted Answer

2 ATP, 2 NADH, and 2 pyruvate

Question 8

Which stage of cellular respiration does NOT occur in the mitochondria?

Accepted Answer

Glycolysis

Question 9

Why are sweating and other body-cooling mechanisms necessary during vigorous exercise?

Accepted Answer

Because only 34% of the energy from glucose is captured as ATP, with the rest released as heat.

Question 10

Which of the following best explains why fats are a more efficient energy storage molecule than polysaccharides in animals?

Accepted Answer

Fats yield more ATP per gram because they have more hydrogen atoms and electrons for oxidation.

Question 11

A patient has a genetic defect that causes their mitochondria to have leaky inner membranes, allowing protons ($$H^+) to $$flow freely across. What is the most likely consequence?

Accepted Answer

Decreased ATP production and increased heat generation.

Question 12

Which of the following is true about fermentation in human muscle cells?

Accepted Answer

Fermentation recycles NAD^+ by reducing pyruvate to lactate.

Question 13

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

ATP is produced directly by the transfer of a phosphate group from an organic molecule to ADP.

Question 14

Which of the following is a correct sequence of events in the complete aerobic breakdown of glucose?

Accepted Answer

Glycolysis → Pyruvate oxidation → Citric acid cycle → Oxidative phosphorylation

Question 15

Which of the following is a function of NAD^+ in cellular respiration?

Accepted Answer

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

Question 16

A person is on a low-fat diet but still gains weight and stores fat. Which of the following best explains this phenomenon?

Accepted Answer

Carbohydrates and proteins can be converted into fat through metabolic pathways.

Question 17

Which of the following is a correct comparison between lactic acid fermentation and alcohol fermentation?

Accepted Answer

Both processes regenerate NAD^+ and allow glycolysis to continue in the absence of oxygen.

Question 18

Which of the following best describes the role of the electron transport chain in mitochondria?

Accepted Answer

It creates a proton gradient that drives ATP synthesis via chemiosmosis.

Question 19

Which of the following would most likely occur if oxygen is absent during cellular respiration?

Accepted Answer

The electron transport chain would stop, and ATP production by oxidative phosphorylation would cease.

Question 20

Which of the following is a real-life example of feedback inhibition in cellular respiration?

Accepted Answer

High levels of ATP inhibit an early enzyme in glycolysis, slowing down glucose breakdown.

Chapter 6: Cells Harvest Chemical Energy – Cellular Respiration and Metabolic Pathways

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