Question 1

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

Accepted Answer

Catabolic pathways release energy by breaking down molecules, and this energy is used by anabolic pathways to build new molecules.

Question 2

A scientist is studying a bacterial enzyme that requires magnesium ions to function. What is the role of magnesium in this context?

Accepted Answer

Magnesium is a cofactor that helps stabilize the enzyme's structure or participates in the reaction.

Question 3

During glycolysis, which molecule is reduced as glucose is oxidized?

Accepted Answer

NAD+

Question 4

Which of the following statements about enzyme activity is correct?

Accepted Answer

Enzyme activity is highest at an optimal temperature and pH, and can decrease if conditions deviate from these values.

Question 5

A patient’s muscle cells are deprived of oxygen during intense exercise. Which metabolic pathway allows ATP production to continue under these conditions?

Accepted Answer

Homolactic fermentation

Question 6

Which of the following best explains why reduction is the term used to describe the gain of electrons in a redox reaction?

Accepted Answer

The molecule’s net charge decreases as it gains negatively charged electrons.

Question 7

In the electron transport chain, what is the primary function of ATP synthase?

Accepted Answer

To use the proton gradient to synthesize ATP from ADP and inorganic phosphate.

Question 8

Which of the following equations correctly represents the net ATP yield from glycolysis per molecule of glucose?

Accepted Answer

$$2\ \mathrm{ATP}$$

Question 9

A bacterial culture is tested with hydrogen peroxide and bubbles are observed. What does this indicate about the bacteria?

Accepted Answer

They produce catalase, which breaks down hydrogen peroxide into water and oxygen.

Question 10

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

ATP is produced by the direct transfer of a phosphate group from a pathway intermediate to ADP.

Question 11

A microbe is found to use nitrate ($$\mathrm{NO}_3^-) as $$its final electron acceptor in respiration. What type of respiration is this?

Accepted Answer

Anaerobic respiration

Question 12

Which of the following is a correct summary of the products of the Krebs cycle per molecule of glucose?

Accepted Answer

$$2\ \mathrm{ATP},\ 6\ \mathrm{NADH},\ 2\ \mathrm{FADH}_2$$

Question 13

Which of the following statements about feedback inhibition is correct?

Accepted Answer

Feedback inhibition slows or stops a metabolic pathway when enough end product has accumulated.

Question 14

A bacterial species is found to be 'oxidase positive.' What does this indicate about its metabolism?

Accepted Answer

It possesses cytochrome c oxidase in its electron transport chain.

Question 15

Which of the following best describes the main function of fermentation in microbial metabolism?

Accepted Answer

To regenerate $$\mathrm{NAD}^+$$ from $$\mathrm{NADH}$$, allowing glycolysis to continue.

Question 16

Which of the following is NOT a product of the complete aerobic breakdown of one molecule of glucose?

Accepted Answer

Ethanol

Question 17

A cell is observed to break down fatty acids into acetyl-CoA, which then enters the Krebs cycle. Which process is responsible for this breakdown?

Accepted Answer

Beta-oxidation

Question 18

Which of the following best explains why enzymes are specific for their substrates?

Accepted Answer

The active site of an enzyme has a unique shape and chemical environment that fits only specific substrates.

Question 19

A laboratory test detects the presence of acetoin in a bacterial culture. Which fermentation pathway is indicated by this result?

Accepted Answer

Butanediol fermentation

Question 20

Which of the following statements about the location of the electron transport chain is correct?

Accepted Answer

In prokaryotes, it is located in the plasma membrane; in eukaryotes, it is located in the inner mitochondrial membrane.

Microbial Metabolism: Pathways, Enzymes, and Energy Production

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