Question 1

Which of the following best describes the main function of ATP in microbial metabolism?

Accepted Answer

ATP serves as the universal energy currency, providing energy for cellular work through the hydrolysis of its high-energy phosphate bonds.

Question 2

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

Accepted Answer

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

Question 3

A bacterium is growing in an environment lacking oxygen but containing nitrate ($$\mathrm{NO_3$^-}). $$Which metabolic process is most likely being used to generate ATP?

Accepted Answer

Anaerobic respiration

Question 4

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

Accepted Answer

Reduction involves the gain of electrons, and oxidation involves the loss of electrons.

Question 5

Which of the following is a primary function of the electron transport chain (ETC) in prokaryotic cells?

Accepted Answer

To create a proton gradient across the membrane, which drives ATP synthesis via ATP synthase

Question 6

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

Accepted Answer

Fermentation does not use the electron transport chain, so most of the energy remains in the end products.

Question 7

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

Accepted Answer

$$38$$ ATP

Question 8

A mutation in a bacterium prevents the regeneration of NAD$$^+$$ from NADH. Which metabolic process would be most directly affected?

Accepted Answer

Glycolysis

Question 9

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

Accepted Answer

Enzymes act as catalysts, lowering the activation energy and increasing the rate of metabolic reactions.

Question 10

Which of the following is an example of feedback inhibition in a metabolic pathway?

Accepted Answer

A product of the pathway binds to an allosteric site on an enzyme early in the pathway, decreasing its activity.

Question 11

Which pathway is responsible for generating precursor metabolites for nucleotide and some amino acid biosynthesis, as well as NADPH for anabolic reactions?

Accepted Answer

Pentose phosphate pathway

Question 12

Which of the following is a correct equation for the regeneration of NAD$$^+$$ during lactic acid fermentation?

Accepted Answer

$$\mathrm{Pyruvate} + \mathrm{NADH} \rightarrow \mathrm{Lactic\ acid} + \mathrm{NAD}^+$$

Question 13

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

Accepted Answer

Catabolic pathways are exergonic and provide energy for anabolic pathways.

Question 14

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

Accepted Answer

Synthesis of ATP from ADP and inorganic phosphate

Question 15

Which of the following is a unique feature of the Entner-Doudoroff pathway compared to glycolysis (EMP pathway)?

Accepted Answer

It produces pyruvate using a unique set of enzymes and is found in some bacteria such as Pseudomonas aeruginosa.

Question 16

Which of the following best explains why cells prefer to catabolize glucose before lactose when both are available?

Accepted Answer

Glucose is more energy-efficient to catabolize and is regulated at the genetic level to be used first.

Question 17

Which of the following is a correct description of gluconeogenesis?

Accepted Answer

It is similar to glycolysis but runs in reverse, synthesizing glucose from non-carbohydrate precursors.

Question 18

Which of the following is a key entry/exit point for amino acid and lipid catabolism and anabolism?

Accepted Answer

Krebs (citric acid) cycle

Question 19

Which of the following is a correct summary of the main goal of fermentation in microbial cells?

Accepted Answer

To regenerate NAD$$^+$$ for glycolysis, allowing continued ATP production via substrate-level phosphorylation

Microbial Metabolism: Pathways, Energy, and Regulation

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