Question 1

Which of the following best describes the role of enzymes in microbial metabolism?

Accepted Answer

Enzymes act as biological catalysts, lowering the activation energy required for reactions to occur under life-supporting conditions.

Question 2

A bacterium is exposed to a non-competitive inhibitor. Which of the following is most likely to occur?

Accepted Answer

The enzyme's shape is altered at a site other than the active site, reducing its activity.

Question 3

Which of the following equations correctly represents the net reaction of glycolysis via the Embden-Meyerhof pathway?

Accepted Answer

$$\mathrm{Glucose} \rightarrow 2\ \mathrm{Pyruvate} + 2\ \mathrm{ATP} + 2\ \mathrm{NADH}$$

Question 4

During aerobic cellular respiration, what is the final electron acceptor in the electron transport chain (ETC)?

Accepted Answer

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

Question 5

Which of the following best explains why fermentation produces less ATP than aerobic respiration?

Accepted Answer

Fermentation only uses substrate-level phosphorylation and does not utilize the electron transport chain for oxidative phosphorylation.

Question 6

A bacterial culture is tested for cytochrome c oxidase activity. Which result would indicate a positive oxidase test?

Accepted Answer

The culture turns blue or purple upon addition of the oxidase reagent.

Question 7

Which of the following statements about anabolic and catabolic pathways is correct?

Accepted Answer

Anabolic pathways are biosynthetic and require energy, while catabolic pathways break down molecules and release energy.

Question 8

A patient is given sulfanilamide to treat a bacterial infection. What is the mechanism of action of this drug?

Accepted Answer

It acts as a competitive inhibitor, blocking the active site of an enzyme involved in folic acid synthesis.

Question 9

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

ATP is generated by the transfer of a phosphate group directly from a substrate to ADP.

Question 10

Which metabolic pathway is primarily responsible for generating NADPH used in anabolic reactions?

Accepted Answer

Pentose Phosphate Pathway (PPP)

Question 11

A bacterium is found to utilize the Entner-Doudoroff pathway. Which of the following is a correct outcome of this pathway?

Accepted Answer

$$1$$ Net ATP$$ \ \&\ 1$$ NADPH (used in anabolic reactions)

Question 12

Which of the following best explains the process of beta-oxidation in microbial metabolism?

Accepted Answer

Beta-oxidation breaks down fatty acids into acetyl-CoA, which enters the Krebs cycle.

Question 13

A microbe is grown in a medium containing urea. Which enzyme would you test for to determine if the microbe can hydrolyze urea, and what is the expected product?

Accepted Answer

Test for urease; expected product is ammonia.

Question 14

Which of the following is an example of feedback inhibition in microbial metabolism?

Accepted Answer

A product of a metabolic pathway binds to an enzyme early in the pathway, decreasing its activity.

Question 15

Which of the following best describes the difference between aerobic and anaerobic respiration in bacteria?

Accepted Answer

Aerobic respiration uses $$\mathrm{O}_2 as $$the final electron acceptor, while anaerobic respiration uses inorganic or organic molecules other than $$\mathrm{O}_2.$$

Question 16

Which of the following is a correct description of chemiosmosis in cellular respiration?

Accepted Answer

Chemiosmosis is the generation of ATP by the movement of protons across a membrane through ATP synthase.

Question 17

A microbe is able to grow using only $$\mathrm{CO}_2 as $$its carbon source and $$\mathrm{H}_2S as $$its energy source. How would you classify this organism?

Accepted Answer

Chemoautotroph

Question 18

Which of the following best explains the process of deamination in protein catabolism?

Accepted Answer

Deamination removes an amino group from an amino acid, allowing the remaining carbon skeleton to enter the Krebs cycle.

Question 19

Which of the following is a correct example of an endergonic reaction in microbial metabolism?

Accepted Answer

Biosynthesis of proteins from amino acids

Microbial Metabolism: Pathways, Enzymes, and Energy Production

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