$$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} \rightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O} + \text{Energy (ATP)}$$

Question 1

Which of the following best describes the main function of mitochondria in eukaryotic cells?

Accepted Answer

They generate ATP through aerobic respiration.

Question 2

What is the correct balanced chemical equation for aerobic cellular respiration?

Accepted Answer

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

Question 3

During which step of aerobic respiration is the majority of ATP produced?

Accepted Answer

Oxidative phosphorylation (electron transport and chemiosmosis)

Question 4

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

Accepted Answer

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

Question 5

If a cell is deprived of oxygen, which process will continue to produce ATP?

Accepted Answer

Glycolysis

Question 6

Which of the following best explains why lactic acid builds up in muscles during intense exercise?

Accepted Answer

Oxygen is not available, so pyruvate is converted to lactic acid to regenerate NAD+.

Question 7

Which of the following is a correct description of substrate-level phosphorylation?

Accepted Answer

ATP is produced directly by transferring a phosphate group from a substrate to ADP.

Question 8

In the feedback inhibition loop shown, what is the role of molecule C?

Accepted Answer

C inhibits Enzyme 1, decreasing the conversion of A to B.

Question 9

Which of the following statements about glycolysis is TRUE?

Accepted Answer

It produces a net gain of 2 ATP per glucose molecule.

Question 10

What is the evolutionary significance of glycolysis?

Accepted Answer

It is an ancient pathway that can function without oxygen, likely used by early prokaryotes.

Question 11

Which of the following best describes the process of oxidative phosphorylation?

Accepted Answer

ATP is produced as protons move down their concentration gradient through ATP synthase.

Question 12

During alcoholic fermentation, what are the main products formed from pyruvate?

Accepted Answer

Ethanol, CO2, and NAD+

Question 13

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

Accepted Answer

Glycolysis → Pyruvate oxidation → Citric acid cycle → Oxidative phosphorylation

Question 14

A patient has a genetic defect that prevents the formation of NAD+. Which step of cellular respiration would be most directly affected?

Accepted Answer

Glycolysis

Question 15

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

Accepted Answer

Fats are broken down into acetyl CoA, which enters the citric acid cycle.

Question 16

Which of the following statements about the electron transport chain is FALSE?

Accepted Answer

It directly produces glucose from carbon dioxide.

Question 17

A scientist adds a chemical that blocks ATP synthase in mitochondria. What immediate effect will this have on the cell?

Accepted Answer

ATP production by oxidative phosphorylation will decrease sharply.

Question 18

Which of the following best describes the role of NADH and FADH2 in cellular respiration?

Accepted Answer

They are electron carriers that donate electrons to the electron transport chain.

Question 19

In a scenario where a person is sprinting at maximum effort, which metabolic pathway is providing the initial 'turbo boost' of energy?

Accepted Answer

Lactic acid fermentation in the cytoplasm

Question 20

Which of the following statements about feedback inhibition in metabolic pathways is correct?

Accepted Answer

The end product of the pathway inhibits the first enzyme, preventing overproduction.

Cellular Respiration: Mechanisms, Pathways, and Evolutionary Context

Study Guide - Practice Questions