Question 1

Which of the following best describes the main difference between catabolic and anabolic pathways in cellular metabolism?

Accepted Answer

Catabolic pathways release energy by breaking down complex molecules, while anabolic pathways require energy to build complex molecules from simpler ones.

Question 2

During aerobic respiration, what is the correct sequence of stages that glucose undergoes to be fully oxidized?

Accepted Answer

Glycolysis → Acetyl CoA Synthesis → Citric Acid Cycle → Electron Transport Chain

Question 3

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

Accepted Answer

$$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6\ \mathrm{O}_2 ightarrow 6\ \mathrm{CO}_2 + 6\ \mathrm{H}_2\mathrm{O} + 	ext{energy}$$

Question 4

Where in the cell does glycolysis occur, and what is its net ATP yield per glucose molecule?

Accepted Answer

Cytoplasm; 2 ATP

Question 5

Which molecule is the final electron acceptor in the electron transport chain during aerobic respiration?

Accepted Answer

O$$_2$$

Question 6

A poison that blocks the function of Complex IV in the electron transport chain would have which of the following effects?

Accepted Answer

Oxygen would no longer be reduced to water, and ATP production by oxidative phosphorylation would stop.

Question 7

Which of the following best explains why fermentation is less efficient than aerobic respiration?

Accepted Answer

Fermentation only partially oxidizes glucose, yielding only 2 ATP per glucose molecule.

Question 8

In the citric acid cycle, what happens to the carbon atoms from acetyl-CoA?

Accepted Answer

They are released as CO$$_2.$$

Question 9

Which of the following statements about the proton gradient in mitochondria is correct?

Accepted Answer

The proton gradient is used by ATP synthase to drive the synthesis of ATP from ADP and Pi.

Question 10

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

Accepted Answer

ATP is produced directly by the transfer of a phosphate group from a substrate to ADP.

Question 11

Which of the following is NOT a product of glycolysis?

Accepted Answer

CO$$_2$$

Question 12

A patient is exposed to cyanide, which binds to iron in Complex IV of the electron transport chain. What immediate effect would you expect in their cells?

Accepted Answer

Cessation of electron flow through the ETC and a rapid drop in ATP synthesis

Question 13

Which of the following best explains why oxygen is essential for aerobic respiration?

Accepted Answer

Oxygen acts as the final electron acceptor in the electron transport chain, allowing continued ATP production.

Question 14

Which of the following statements about anaerobic respiration is correct?

Accepted Answer

Anaerobic respiration can use molecules like nitrate (NO$$_3^-) or $$sulfate (SO$$_4$$^{2-}$$) as final electron acceptors.

Question 15

Which of the following is a key difference between alcohol fermentation and lactate fermentation?

Accepted Answer

Alcohol fermentation produces CO$$_2$$, while lactate fermentation does not.

Question 16

If a cell is deprived of oxygen, which of the following processes will continue to function?

Accepted Answer

Glycolysis

Question 17

Which of the following best describes the fate of NADH produced during glycolysis under anaerobic conditions in muscle cells?

Accepted Answer

NADH is oxidized by transferring electrons to pyruvate, forming lactate.

Question 18

Which of the following statements about the energy yield from the complete aerobic oxidation of one molecule of glucose is correct?

Accepted Answer

It yields a net total of 36-38 ATP.

Question 19

Which of the following best explains why fats yield more ATP per gram than carbohydrates when used as an energy source?

Accepted Answer

Fatty acids are broken down into acetyl-CoA, which enters the citric acid cycle and produces more NADH and FADH$$_2$$ per gram than carbohydrates.

Question 20

A mutation prevents the regeneration of oxaloacetate in the citric acid cycle. What would be the most immediate consequence for cellular respiration?

Accepted Answer

The citric acid cycle would halt, preventing further oxidation of acetyl-CoA.

Cellular Respiration and Metabolism: An Overview

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