Question 1

Which of the following best describes the difference between catabolism and anabolism in microbial metabolism?

Accepted Answer

Catabolism is the breakdown of complex molecules into simpler ones, releasing energy; anabolism is the synthesis of complex molecules from simpler ones, requiring energy input.

Question 2

Which of the following equations correctly represents the hydrolysis of ATP and its standard free energy change?

Accepted Answer

$$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + \mathrm{P}_i$$; $$\Delta G$$^{\circ\prime}$$ = -7.3\ \mathrm{kcal/mol}$$

Question 3

Which of the following is NOT a major form of cellular work powered by ATP in microbes?

Accepted Answer

Passive diffusion of gases

Question 4

In the context of redox reactions, which statement is correct?

Accepted Answer

Oxidation is the loss of electrons, and reduction is the gain of electrons.

Question 5

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

It involves the direct transfer of a phosphate group from a phosphorylated intermediate to ADP, catalyzed by a soluble enzyme.

Question 6

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

Accepted Answer

Substrate-level phosphorylation occurs in the cytoplasm, while oxidative phosphorylation is membrane-associated.

Question 7

During fermentation, what is the primary purpose of regenerating NAD$$^+$$?

Accepted Answer

To allow glycolysis to continue by providing an electron acceptor for NADH.

Question 8

Which of the following best describes a chemolithoautotroph?

Accepted Answer

An organism that uses inorganic compounds as an energy and electron source and CO$$_2 as a $$carbon source.

Question 9

Which of the following statements about the electron transport chain (ETC) in prokaryotes is correct?

Accepted Answer

The ETC is located in the plasma membrane and transfers electrons from donors to acceptors with decreasing energy.

Question 10

Which of the following is a direct result of the proton motive force (PMF) generated by the electron transport chain?

Accepted Answer

Synthesis of ATP via ATP synthase

Question 11

In aerobic respiration, what is the final electron acceptor?

Accepted Answer

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

Question 12

Which of the following best explains why anaerobic respiration yields less ATP than aerobic respiration?

Accepted Answer

Anaerobic respiration uses electron acceptors with lower reduction potentials than oxygen, resulting in less energy conservation.

Question 13

Which of the following is true regarding the chemiosmotic theory?

Accepted Answer

The return flow of protons through ATP synthase drives the phosphorylation of ADP to ATP.

Question 14

Which of the following is a distinguishing feature of cyclic photophosphorylation in phototrophs?

Accepted Answer

Electrons return to the original chlorophyll molecule, and only ATP is produced.

Question 15

Which of the following statements about enzymes is correct?

Accepted Answer

Enzymes lower the activation energy and increase the rate of reaction without changing the overall free energy change ($$\Delta G).$$

Question 16

Which of the following is an example of a competitive inhibitor?

Accepted Answer

A molecule that binds to the active site, preventing substrate binding.

Question 17

Which of the following best describes feedback inhibition in metabolic pathways?

Accepted Answer

The end-product of a pathway inhibits an enzyme near the start of the pathway.

Question 18

A bacterium is growing in an environment lacking oxygen but containing nitrate ($$\mathrm{NO}_3^-). $$Which metabolic process is most likely being used for energy conservation?

Accepted Answer

Anaerobic respiration

Question 19

Which of the following is a function of the proton motive force (PMF) in bacteria?

Accepted Answer

Synthesis of ATP, active transport, and flagellar rotation

Microbial Metabolism: Mechanisms, Diversity, and Energy Conservation

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