Question 1

Which of the following statements best describes the relationship between catabolism and anabolism in cellular metabolism?

Accepted Answer

Catabolism breaks down complex molecules to release energy, which is then used by anabolism to build macromolecules from simpler precursors.

Question 2

Which of the following is NOT a function of ATP in cellular metabolism?

Accepted Answer

Acting as a precursor metabolite for macromolecule synthesis.

Question 3

Which of the following equations correctly represents substrate-level phosphorylation?

Accepted Answer

$$ \mathrm{Glucose} + 2\mathrm{NAD}^+ + 2\mathrm{ADP} + 2\mathrm{P_i} \rightarrow 2\mathrm{Pyruvate} + 2\mathrm{NADH} + 2\mathrm{ATP} + 2\mathrm{H}_2\mathrm{O} $$

Question 4

Which of the following best explains why enzymes are considered biological catalysts?

Accepted Answer

They lower the activation energy, increasing the likelihood and rate of a reaction without being consumed.

Question 5

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the active site, preventing substrate binding.

Question 6

Which of the following is a correct description of the role of electron carriers in metabolism?

Accepted Answer

They transfer electrons from one molecule to another during redox reactions.

Question 7

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

Accepted Answer

2 ATP and 2 NADH

Question 8

Which of the following is NOT a product of the Krebs cycle per glucose molecule?

Accepted Answer

4 Pyruvate

Question 9

In aerobic respiration, what is the final electron acceptor in the electron transport chain?

Accepted Answer

Oxygen ($$ \mathrm{O}_2 )$$

Question 10

Which process is responsible for the majority of ATP production during cellular respiration?

Accepted Answer

Electron transport chain and chemiosmosis

Question 11

Which of the following statements about fermentation is TRUE?

Accepted Answer

Fermentation regenerates NAD+ by transferring electrons to an organic molecule.

Question 12

Which of the following best describes the role of the Calvin-Benson cycle in photosynthesis?

Accepted Answer

It fixes carbon dioxide into organic molecules using ATP and NADPH.

Question 13

Which of the following is an example of an amphibolic pathway?

Accepted Answer

Krebs cycle

Question 14

A cell is exposed to a noncompetitive inhibitor. What is the most likely effect on enzyme activity?

Accepted Answer

The inhibitor binds to an allosteric site, changing the enzyme's shape and reducing activity.

Question 15

Which of the following regulatory mechanisms allows a cell to stop an anabolic pathway when the end product is abundant?

Accepted Answer

Feedback inhibition

Question 16

Which of the following is a correct equation for the overall process of 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 17

Which of the following is a key difference between substrate-level phosphorylation and oxidative phosphorylation?

Accepted Answer

Substrate-level phosphorylation directly transfers a phosphate group to ADP, while oxidative phosphorylation uses a proton gradient and ATP synthase.

Question 18

Which of the following best explains why cells use different coenzymes for amphibolic pathways?

Accepted Answer

To ensure that catabolic and anabolic reactions do not occur simultaneously and waste energy.

Question 19

Which of the following is a product of lipid catabolism that enters the Krebs cycle?

Accepted Answer

Acetyl-CoA

Question 20

A bacterium is growing in an environment with both glucose and lactose available. According to metabolic regulation principles, which sugar will the cell catabolize first and why?

Accepted Answer

Glucose, because cells preferentially catabolize the more energy-efficient substrate first.

Microbial Metabolism: Chemical Reactions and Pathways

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