Question 1

Which of the following best describes the role of electron donors and electron acceptors in microbial metabolism?

Accepted Answer

Electron donors direct electrons to electron acceptors, facilitating energy conservation and ATP generation.

Question 2

Which equation correctly represents the substrate-level phosphorylation that occurs during glycolysis?

Accepted Answer

$$\mathrm{Glucose} + 2\mathrm{ADP} + 2\mathrm{P_i} \rightarrow 2\mathrm{Pyruvate} + 2\mathrm{ATP} + 2\mathrm{H_2O}$$

Question 3

A microorganism that uses hydrogen sulfide ($$\mathrm{H_2S}) as an $$electron donor and carbon dioxide ($$\mathrm{CO_2$}) as a $$carbon source is classified as:

Accepted Answer

Chemolithoautotroph

Question 4

Which statement about enzymes is correct?

Accepted Answer

Enzymes are highly specific biological catalysts, often proteins, that increase reaction rates by lowering activation energy.

Question 5

What is the main difference between fermentation and respiration in terms of electron acceptors?

Accepted Answer

Fermentation uses organic compounds as both electron donors and acceptors, while respiration uses external electron acceptors such as $$\mathrm{O_2$} or$$ $$\mathrm{NO_3$^-}.$$

Question 6

Which of the following is a correct description of the proton motive force generated during electron transport?

Accepted Answer

Protons are released outside the membrane, creating a pH gradient and an electrochemical potential with the inside negative and alkaline.

Question 7

Which of the following compounds is a common energy storage polymer in prokaryotes?

Accepted Answer

Glycogen

Question 8

What is the function of cytochromes in the electron transport chain?

Accepted Answer

They accept and donate a single electron via the iron atom in heme.

Question 9

Which pathway is the major means for direct synthesis of NADPH for deoxyribonucleotide and fatty acid biosynthesis?

Accepted Answer

Pentose phosphate pathway

Question 10

A bacterium is found to use nitrate ($$\mathrm{NO_3$^-}) as $$its terminal electron acceptor. Which process is this organism performing?

Accepted Answer

Anaerobic respiration

Question 11

Which of the following statements about coenzymes is true?

Accepted Answer

Coenzymes are loosely bound and most are derivatives of vitamins.

Question 12

During fatty acid biosynthesis in bacteria, which molecule holds the growing fatty acid chain?

Accepted Answer

Acyl carrier protein (ACP)

Question 13

Which metabolic class of microorganisms conserves energy from organic chemicals?

Accepted Answer

Chemoorganotrophs

Question 14

What is the main source of carbon for autotrophic microorganisms?

Accepted Answer

Carbon dioxide ($$\mathrm{CO_2$})$$

Question 15

Which process is responsible for the synthesis of glucose from phosphoenolpyruvate?

Accepted Answer

Gluconeogenesis

Question 16

Which of the following is true regarding the effect of temperature on fatty acid biosynthesis in bacteria?

Accepted Answer

Higher temperatures favor longer, more saturated fatty acids.

Question 17

Which of the following is NOT a function of a catalyst in a biochemical reaction?

Accepted Answer

Affects the equilibrium of the reaction

Question 18

Which of the following statements about phototrophy is correct?

Accepted Answer

Photoautotrophs use ATP and $$\mathrm{CO_2$}$$ for biosynthesis.

Question 19

Which of the following is a precursor for glycogen biosynthesis in prokaryotes?

Accepted Answer

Adenosine diphosphoglucose (ADPG)

Question 20

Which enzyme is responsible for incorporating ammonia into amino acids during biosynthesis?

Accepted Answer

Glutamine synthetase

Ch.3 - Microbial Metabolism: Energy, Enzymes, and Biosynthesis

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