Question 1

Which of the following best describes how ATP powers cellular work?

Accepted Answer

ATP hydrolysis releases energy that is coupled to endergonic reactions, often through phosphorylation of intermediates.

Question 2

What is the main function of mitochondria in eukaryotic cells?

Accepted Answer

To harvest chemical energy from food and produce ATP.

Question 3

Which of the following equations correctly represents the hydrolysis of ATP?

Accepted Answer

$$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + \mathrm{P}_i$$

Question 4

Why is ATP often compared to a rechargeable battery in biological systems?

Accepted Answer

Because ATP can be regenerated from ADP and $$\mathrm{P}_i$$ using energy from food metabolism.

Question 5

Which of the following statements about redox reactions is correct?

Accepted Answer

Oxidation is the loss of electrons, and reduction is the gain of electrons.

Question 6

In the following reaction, which molecule is the reducing agent?

$$\mathrm{A} + \mathrm{B} \rightarrow \mathrm{A}^+ + \mathrm{B}^-$$

Accepted Answer

A, because it loses electrons to B.

Question 7

Which process in cellular respiration produces the most ATP?

Accepted Answer

Oxidative phosphorylation (electron transport chain and chemiosmosis)

Question 8

What is the role of NAD+ in cellular respiration?

Accepted Answer

It acts as an electron carrier, becoming reduced to NADH.

Question 9

Which of the following best explains why energy coupling is essential in cells?

Accepted Answer

It enables the energy released from exergonic reactions to drive endergonic reactions.

Question 10

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

Accepted Answer

It involves the direct transfer of a phosphate group from a substrate to ADP to form ATP.

Question 11

A scientist adds a chemical that blocks ATP synthase in mitochondria. What is the most immediate effect on the cell?

Accepted Answer

The cell will be unable to produce ATP via chemiosmosis.

Question 12

Which of the following best describes the difference between aerobic and anaerobic respiration?

Accepted Answer

Aerobic respiration uses oxygen as the final electron acceptor, while anaerobic respiration does not.

Question 13

Which of the following is a correct statement about the energy changes during oxidation and reduction?

Accepted Answer

Reduced molecules have more potential energy than oxidized molecules.

Question 14

In the context of cellular respiration, what is chemiosmosis?

Accepted Answer

The movement of protons (H+) across a membrane to drive ATP synthesis via ATP synthase.

Question 15

A patient’s muscle cells are unable to regenerate ATP from ADP and Pi efficiently. Which cellular process is most likely impaired?

Accepted Answer

Cellular respiration

Question 16

Which of the following best describes the role of phosphorylation in cellular processes?

Accepted Answer

It often activates proteins or makes substrates more reactive by adding a phosphate group.

Question 17

Which of the following is an example of energy coupling in a cell?

Accepted Answer

The use of ATP hydrolysis to drive the synthesis of glutamine from glutamic acid and ammonia.

Question 18

Which of the following statements about electron carriers such as NAD+ and FAD is correct?

Accepted Answer

They shuttle electrons by alternating between reduced and oxidized forms.

Question 19

Which of the following best explains why the electron transport chain is necessary in cellular respiration?

Accepted Answer

It allows for the controlled release of energy from electrons to synthesize ATP, rather than releasing all energy as heat.

Question 20

If a cell is unable to reduce NAD+ to NADH, which process would be directly affected?

Accepted Answer

The cell would be unable to carry out glycolysis and the citric acid cycle efficiently.

ATP, Redox Reactions, and Cellular Respiration: Energy Flow in Cells

Study Guide - Practice Questions