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

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

Question 1

Which of the following best describes the relationship between free energy change ($$\Delta G) $$and the direction of a chemical reaction at constant temperature and pressure?

Accepted Answer

A reaction proceeds spontaneously in the direction where $$\Delta G is $$negative.

Question 2

During cellular respiration, which molecule acts as the final electron acceptor in the electron transport chain, and what is the product formed?

Accepted Answer

Oxygen ($$O_2$$); water ($$H_2O)$$

Question 3

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

Accepted Answer

$$C_6H_{12}O_6$ + 6O_2 ightarrow 6CO_2 + 6H_2O + 	ext{energy (ATP + heat)}$$

Question 4

Which of the following best explains why ATP is considered the 'energy currency' of the cell?

Accepted Answer

ATP can directly transfer a phosphate group to other molecules, releasing energy for cellular work.

Question 5

A muscle cell is deprived of oxygen. Which process will allow it to continue producing ATP, and what is the main byproduct?

Accepted Answer

Lactic acid fermentation; lactate

Question 6

Which of the following statements about the role of NAD$$^+ in $$cellular respiration is correct?

Accepted Answer

NAD$$^+$$ acts as an electron carrier, accepting electrons during glycolysis and the citric acid cycle.

Question 7

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 8

If a poison inhibits the enzyme ATP synthase, which part of cellular respiration is directly affected, and what is the immediate consequence?

Accepted Answer

Electron transport chain; ATP cannot be synthesized from ADP and $$P_i$$

Question 9

A patient has a genetic defect that reduces the efficiency of their mitochondrial electron transport chain. Which of the following would you expect to observe as a result?

Accepted Answer

Decreased oxygen consumption and increased reliance on fermentation

Question 10

Which of the following best describes the role of chemiosmosis in ATP production?

Accepted Answer

It involves the movement of protons down their concentration gradient through ATP synthase, driving the synthesis of ATP.

Question 11

Which of the following changes would most likely increase the rate of a chemical reaction according to the concept of free energy?

Accepted Answer

Decreasing the free energy of the products relative to the reactants

Question 12

During glycolysis, what is the net gain of ATP and NADH molecules per molecule of glucose?

Accepted Answer

2 ATP and 2 NADH

Question 13

Which of the following best explains why fermentation is less efficient than aerobic respiration in terms of ATP yield?

Accepted Answer

Fermentation does not fully oxidize glucose, so less energy is extracted.

Question 14

If a cell's supply of NAD$$^+ is $$depleted, which stage of cellular respiration would be most immediately affected?

Accepted Answer

Glycolysis

Question 15

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 16

A scientist disrupts the mitochondrial inner membrane in a cell. Which process will be most directly impaired?

Accepted Answer

Electron transport chain and chemiosmosis

Question 17

Which of the following best describes the fate of pyruvate in the absence of oxygen in human muscle cells?

Accepted Answer

It is converted to lactate to regenerate NAD$$^+.$$

Question 18

If a mutation caused the enzyme phosphofructokinase to become nonfunctional, what would be the most immediate effect on cellular respiration?

Accepted Answer

Glycolysis would stop, preventing ATP production from glucose.

Question 19

Which of the following best explains how the structure of the mitochondrial inner membrane supports its function in cellular respiration?

Accepted Answer

Its folded cristae increase surface area for electron transport chains and ATP synthase complexes.

Question 20

A drug blocks the regeneration of NAD$$^+$$ from NADH. Which process would be most directly affected, and what would be the likely cellular consequence?

Accepted Answer

Glycolysis; ATP production would decrease due to lack of NAD$$^+.$$

Cellular Respiration: Free Energy, Chemical Equilibrium, and Metabolic Pathways

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