Question 1

Which of the following best describes the process of substrate-level phosphorylation?

Accepted Answer

It is the direct transfer of a phosphate group to ADP from a phosphorylated intermediate.

Question 2

A bacterium is growing in an environment lacking oxygen. Which metabolic pathway is it most likely to use to generate ATP?

Accepted Answer

Fermentation

Question 3

Which of the following is NOT a function of enzymes in microbial metabolism?

Accepted Answer

Enzymes are consumed during the reaction and cannot be reused.

Question 4

During glycolysis, glucose is converted into which of the following products?

Accepted Answer

Two molecules of pyruvate

Question 5

Which of the following statements about competitive enzyme inhibition is correct?

Accepted Answer

A competitive inhibitor binds to the active site of the enzyme, preventing substrate binding.

Question 6

Which molecule acts as the final electron acceptor in aerobic respiration?

Accepted Answer

O$$_2$$

Question 7

A mutation causes a bacterium's electron transport chain to stop functioning. Which of the following would most likely occur?

Accepted Answer

The cell would rely on fermentation to regenerate NAD$$^+.$$

Question 8

Which of the following best explains why enzymes are sensitive to changes in temperature and pH?

Accepted Answer

Changes in temperature and pH can alter the enzyme's three-dimensional structure, affecting its activity.

Question 9

Which of the following is a correct sequence of events in aerobic respiration?

Accepted Answer

Glycolysis $$\rightarrow$$ Krebs cycle $$\rightarrow$$ Electron Transport Chain

Question 10

Which of the following statements about NAD$$^+$$ and FAD is TRUE?

Accepted Answer

They act as electron carriers during cellular respiration.

Question 11

A patient is given an antibiotic that acts as a noncompetitive inhibitor of a bacterial enzyme. What is the most likely effect on the enzyme's activity?

Accepted Answer

The enzyme's activity will decrease because the inhibitor binds to an allosteric site, altering the enzyme's shape.

Question 12

Which of the following best describes the main purpose of fermentation in microbial cells?

Accepted Answer

To regenerate NAD$$^+$$ for glycolysis in the absence of an electron transport chain.

Question 13

Which of the following is a product of the Krebs cycle?

Accepted Answer

CO$$_2$$

Question 14

Which process is responsible for the majority of ATP production during aerobic respiration in prokaryotes?

Accepted Answer

Oxidative phosphorylation

Question 15

A scientist measures the ATP yield from one molecule of glucose in a prokaryotic cell. Which value is closest to the theoretical maximum?

Accepted Answer

$$\sim38 $$ATP

Question 16

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

Accepted Answer

Fermentation produces much less ATP per molecule of glucose than aerobic respiration.

Question 17

Which of the following is an example of an anabolic reaction in microbial metabolism?

Accepted Answer

Synthesis of amino acids from precursor metabolites

Question 18

A researcher adds a competitive inhibitor to a solution containing an enzyme and its substrate. Which of the following would most likely increase the rate of the enzyme-catalyzed reaction?

Accepted Answer

Increasing the concentration of substrate

Question 19

Which of the following best describes the role of the electron transport chain (ETC) in cellular respiration?

Accepted Answer

It uses energy from electrons to pump protons across a membrane, creating a gradient used to synthesize ATP.

Question 20

Which of the following is a likely consequence if a cell's environment becomes too acidic for its enzymes?

Accepted Answer

The enzymes may denature, losing their functional shape and activity.

Microbial Metabolism: Enzymes, Energy, and Catabolic Pathways

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