Question 1

Which of the following best describes the overall chemical reaction 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 2

During the process of glycolysis, which of the following statements is correct regarding the energy investment and energy payoff phases?

Accepted Answer

The energy investment phase uses 2 ATP molecules, while the energy payoff phase produces 4 ATP molecules and 2 NADH molecules.

Question 3

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

Accepted Answer

$$\mathrm{O_2$} ($$oxygen)

Question 4

In the redox reaction below, which molecule is being oxidized and which is being reduced?

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

Accepted Answer

Glucose is oxidized; oxygen is reduced.

Question 5

Which of the following best explains why NADH yields more ATP than FADH$$_2$$ during oxidative phosphorylation?

Accepted Answer

NADH donates electrons to Complex I, resulting in more protons pumped across the membrane compared to FADH$$_2$$, which donates to Complex II.

Question 6

Which process occurs in the cytosol of eukaryotic cells and does not require oxygen?

Accepted Answer

Glycolysis

Question 7

A poison that blocks ATP synthase would directly prevent which of the following?

Accepted Answer

The production of ATP from ADP and inorganic phosphate during chemiosmosis

Question 8

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

The direct transfer of a phosphate group from a substrate to ADP to form ATP

Question 9

During the citric acid cycle, which molecule combines with acetyl CoA to form citrate?

Accepted Answer

Oxaloacetate

Question 10

Which of the following statements about the role of oxygen in cellular respiration is correct?

Accepted Answer

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

Question 11

If a cell is exposed to cyanide, which inhibits Complex IV of the electron transport chain, what is the most immediate effect?

Accepted Answer

Electron flow through the electron transport chain stops, halting ATP production by oxidative phosphorylation.

Question 12

Which of the following is a correct pairing of process and location in eukaryotic cells?

Accepted Answer

Pyruvate oxidation – mitochondrial matrix

Question 13

Which of the following best explains why an initial investment of ATP is required during glycolysis?

Accepted Answer

It provides the activation energy needed to destabilize glucose and allow subsequent breakdown.

Question 14

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

Accepted Answer

Glycolysis → Pyruvate oxidation → Citric acid cycle → Oxidative phosphorylation

Question 15

Which of the following statements about ATP synthase is correct?

Accepted Answer

ATP synthase uses the energy of the proton gradient to catalyze the formation of ATP from ADP and inorganic phosphate.

Question 16

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

Accepted Answer

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

Question 17

Why is there a difference in the theoretical yield of ATP per glucose molecule between prokaryotes and eukaryotes?

Accepted Answer

Eukaryotes must transport NADH from glycolysis into mitochondria, which requires energy, reducing net ATP yield.

Question 18

Which of the following is a direct output of pyruvate oxidation?

Accepted Answer

Acetyl CoA

Question 19

A patient with a genetic defect in the enzyme that converts pyruvate to acetyl CoA would have difficulty with which process?

Accepted Answer

Entering the citric acid cycle and producing ATP via aerobic respiration

Question 20

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

Accepted Answer

It transfers electrons from NADH and FADH$$_2 to $$oxygen, pumping protons to create a gradient used for ATP synthesis.

Cellular Respiration: Key Concepts, Terms, and Study Strategies

Study Guide - Practice Questions