Q: Which of the following equations correctly represents the overall chemical reaction for aerobic cellular respiration?

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

Question 1

Which of the following best describes the relationship between free energy change ($$\Delta G) $$and chemical equilibrium in a biological reaction?

Accepted Answer

At equilibrium, $$\Delta G = 0$$, and there is no net change in reactant or product concentrations.

Question 2

During cellular respiration, which molecule acts as the final electron acceptor in the electron transport chain, and what is the consequence if this molecule is unavailable?

Accepted Answer

O$$_2$$; ATP production via oxidative phosphorylation ceases, forcing the cell to rely on fermentation.

Question 3

Which of the following equations correctly represents the overall chemical reaction 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 4

Which stage of cellular respiration produces the most ATP, and through which process is this ATP generated?

Accepted Answer

Electron transport chain; oxidative phosphorylation

Question 5

If a cell is deprived of oxygen, which metabolic pathway allows it to continue producing ATP, and what is the main product of this pathway in muscle cells?

Accepted Answer

Fermentation; lactic acid

Question 6

Which of the following best explains why NAD$$^+$$ regeneration is essential for continued ATP production during glycolysis?

Accepted Answer

NAD$$^+ is $$required to accept electrons during glycolysis, and without regeneration, glycolysis would halt due to lack of electron acceptors.

Question 7

A mutation disrupts the structure of the inner mitochondrial membrane. Which process would be most directly affected?

Accepted Answer

Electron transport chain and chemiosmosis

Question 8

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 9

During intense exercise, muscle cells switch to anaerobic metabolism. Which statement best explains the fate of pyruvate under these conditions?

Accepted Answer

Pyruvate is converted to lactic acid to regenerate NAD$$^+$$ for glycolysis.

Question 10

Which of the following best describes the role of the proton gradient in ATP synthesis during cellular respiration?

Accepted Answer

The proton gradient drives the rotation of ATP synthase, catalyzing the formation of ATP from ADP and Pi.

Question 11

Which of the following metabolic pathways is most likely to be affected if a cell's supply of NAD$$^+ is $$depleted?

Accepted Answer

Glycolysis

Question 12

A cell is exposed to cyanide, which inhibits cytochrome c oxidase in the electron transport chain. What is the most immediate effect on cellular respiration?

Accepted Answer

Electron transport halts, preventing ATP synthesis via oxidative phosphorylation.

Question 13

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

Accepted Answer

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

Question 14

Which of the following best explains how altering one enzyme in a metabolic pathway can affect upstream and downstream reactions?

Accepted Answer

Disrupting one enzyme can cause accumulation of its substrate and reduce the production of downstream products.

Question 15

Which of the following is NOT a major stage of cellular respiration?

Accepted Answer

Photosynthesis

Question 16

Which molecule is oxidized during glycolysis, and what is the net ATP yield per glucose molecule?

Accepted Answer

Glucose; 2 ATP

Question 17

Which of the following reactions is an example of a catabolic pathway?

Accepted Answer

Breakdown of glucose to CO$$_2$$ and H$$_2O $$during cellular respiration

Question 18

Which of the following statements about the citric acid cycle is correct?

Accepted Answer

It generates NADH and FADH$$_2$$ that carry electrons to the electron transport chain.

Question 19

Which of the following best describes chemiosmosis in cellular respiration?

Accepted Answer

The movement of protons down their concentration gradient through ATP synthase to generate ATP.

Question 20

Which of the following is a characteristic of a reaction that has reached chemical equilibrium?

Accepted Answer

The rates of the forward and reverse reactions are equal.

Cellular Respiration, Free Energy, and Metabolic Pathways: Study Notes

Study Guide - Practice Questions

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