Question 1

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

Accepted Answer

Catabolic pathways break larger molecules into smaller products and release energy, while anabolic pathways synthesize large molecules from smaller ones and require energy input.

Question 2

Which of the following statements about redox reactions in microbial metabolism is CORRECT?

Accepted Answer

A molecule is oxidized when it loses an electron, a hydrogen atom, or gains an oxygen atom.

Question 3

Which of the following electron carriers can carry two electrons as part of two hydrogen atoms?

Accepted Answer

FAD

Question 4

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

Accepted Answer

Electron transport chain and oxidative phosphorylation

Question 5

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

Accepted Answer

$$\mathrm{PEP} + \mathrm{ADP} \rightarrow \mathrm{Pyruvate} + \mathrm{ATP}$$

Question 6

Which of the following best explains why sulfa drugs inhibit bacterial growth?

Accepted Answer

They act as structural analogs of PABA, competitively inhibiting the enzyme needed for folic acid synthesis.

Question 7

Which of the following is a correct description of a holoenzyme?

Accepted Answer

A complete, active enzyme consisting of an apoenzyme bound to its cofactor and/or coenzyme.

Question 8

Which of the following factors does NOT directly affect enzyme activity?

Accepted Answer

Oxygen concentration

Question 9

A patient is given a drug that acts as a non-competitive inhibitor of a bacterial enzyme. What is the most likely mechanism of action?

Accepted Answer

The drug binds to an allosteric site, changing the shape of the active site and reducing enzyme activity.

Question 10

Which of the following best describes feedback inhibition in a metabolic pathway?

Accepted Answer

The end product of a pathway acts as an allosteric inhibitor of an enzyme early in the pathway.

Question 11

Which of the following is the correct net ATP yield from one molecule of glucose during aerobic respiration in prokaryotes?

Accepted Answer

$$38$$

Question 12

Which of the following is the final electron acceptor in aerobic respiration?

Accepted Answer

$$\mathrm{O}_2$$

Question 13

Which enzyme catalyzes the transfer of electrons from NADH to ubiquinone in the electron transport chain?

Accepted Answer

NADH dehydrogenase

Question 14

Which of the following best describes the role of ATP synthase in cellular respiration?

Accepted Answer

It uses the proton gradient to synthesize ATP from ADP and inorganic phosphate.

Question 15

Which of the following is a product of the Krebs cycle per molecule of glucose?

Accepted Answer

Six NADH

Question 16

Which of the following statements about fermentation is TRUE?

Accepted Answer

Fermentation regenerates NAD+ from NADH, allowing glycolysis to continue in the absence of oxygen.

Question 17

Which of the following best explains why increasing substrate concentration does not always increase enzyme activity?

Accepted Answer

All active sites of the enzyme become saturated, so further increases in substrate concentration have no effect.

Question 18

Which of the following is a correct equation for the oxidative phosphorylation of ADP to ATP?

Accepted Answer

$$\mathrm{ADP} + \mathrm{P_i} + \mathrm{H}^+_{out} \rightarrow \mathrm{ATP} + \mathrm{H}_2\mathrm{O} + \mathrm{H}^+_{in}$$

Question 19

Which of the following is a function of coenzymes in microbial metabolism?

Accepted Answer

They serve as non-protein, organic molecules that assist enzymes, often derived from vitamins.

Microbial Metabolism: Catabolism, Anabolism, Enzymes, and Energy Production

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