Q: Which of the following equations correctly represents the overall reaction for aerobic respiration?

$$\mathrm{C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{energy}}$$

Question 1

Which of the following best describes the main difference between substrate-level phosphorylation and oxidative phosphorylation in microbial metabolism?

Accepted Answer

Substrate-level phosphorylation directly transfers a phosphate group to ADP from a phosphorylated intermediate, while oxidative phosphorylation uses the energy from a proton gradient generated by the electron transport chain to synthesize ATP.

Question 2

In prokaryotes, where does the electron transport chain (ETC) primarily occur?

Accepted Answer

On the inner face of the plasma membrane

Question 3

Which of the following is a possible terminal electron acceptor during anaerobic respiration in prokaryotes?

Accepted Answer

$$\mathrm{NO_3$^-} ($$nitrate)

Question 4

A bacterium is growing in an environment lacking oxygen but containing nitrate. Which metabolic pathway is it most likely to use for energy production?

Accepted Answer

Anaerobic respiration

Question 5

Which of the following statements about the citric acid cycle (TCA cycle) is TRUE?

Accepted Answer

It generates precursors for biosynthetic pathways such as amino acids, nucleic acids, and fatty acids.

Question 6

What is the main function of the proton motive force (PMF) generated by the electron transport chain?

Accepted Answer

To drive ATP synthesis via ATP synthase

Question 7

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

Accepted Answer

Terminal electron acceptors used in anaerobic respiration have a lower reduction potential than $$\mathrm{O_2$}$$, resulting in less energy released per electron transferred.

Question 8

Which of the following is a key reason why some prokaryotes reverse the TCA cycle?

Accepted Answer

To fix $$\mathrm{CO_2$}$$ and generate precursors for anabolic pathways

Question 9

A chemolithotrophic bacterium uses $$\mathrm{Fe$$^{2+}$$} as an $$electron donor and $$\mathrm{O_2$} as an $$electron acceptor. Which of the following statements is correct?

Accepted Answer

It requires more cycles of the electron transport chain to generate one ATP compared to using $$\mathrm{H_2$} as an $$electron donor.

Question 10

Which of the following equations correctly represents the overall reaction for aerobic respiration?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$ + 6O_2 ightarrow 6CO_2 + 6H_2O + 	ext{energy}}$$

Question 11

Which of the following is NOT a function of the electron transport chain in prokaryotes?

Accepted Answer

Directly synthesizing glucose from CO2

Question 12

In the absence of a terminal electron acceptor, which metabolic pathway is most likely to be used by a chemoorganotrophic bacterium?

Accepted Answer

Fermentation

Question 13

Which of the following best describes the role of NADH in cellular respiration?

Accepted Answer

It donates electrons to the electron transport chain, contributing to the generation of a proton motive force.

Question 14

Which of the following is a product of the pyruvate dehydrogenase complex reaction?

Accepted Answer

Acetyl-CoA

Question 15

Which of the following is a key difference between energy metabolism in eukaryotes and prokaryotes?

Accepted Answer

In eukaryotes, the citric acid cycle occurs in the mitochondrial matrix, while in prokaryotes it occurs in the cytoplasm.

Question 16

Which of the following best explains why the citric acid cycle is considered a metabolic hub?

Accepted Answer

It provides intermediates for the synthesis of amino acids, nucleotides, and other biomolecules.

Question 17

Which of the following is a correct description of chemiosmotic coupling?

Accepted Answer

The use of a proton gradient across a membrane to drive ATP synthesis via ATP synthase.

Question 18

A bacterium is found to use $$\mathrm{SO_4$^{2-}} as a $$terminal electron acceptor. Which type of metabolism is this organism most likely performing?

Accepted Answer

Anaerobic respiration

Question 19

Which of the following is a direct product of the citric acid cycle that feeds into the electron transport chain?

Accepted Answer

NADH

Microbial Metabolic Diversity: Catabolism, Respiration, and Energy Conservation

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