Q: Which of the following equations correctly represents the net reaction for aerobic respiration of glucose in Escherichia coli?

$$\text{Glucose} + 6\,\text{O}_2 \rightarrow 6\,\text{CO}_2 + 6\,\text{H}_2\text{O} + 38\,\text{ATP}$$

Question 1

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

Accepted Answer

Catabolism breaks down complex molecules to release energy, while anabolism uses energy to build cellular materials.

Question 2

Which of the following is the main mechanism by which fermentative microbes generate ATP?

Accepted Answer

Substrate-level phosphorylation

Question 3

In the electron transport chain, electrons are transferred from carriers with more negative $$\Delta E_0$' to $$those with more positive $$\Delta E_0$'. $$What is the significance of this arrangement?

Accepted Answer

It provides free energy to pump protons across the membrane, generating a proton motive force.

Question 4

Which of the following equations correctly represents the net reaction for aerobic respiration of glucose in Escherichia coli?

Accepted Answer

$$	ext{Glucose} + 6\,	ext{O}_2 ightarrow 6\,	ext{CO}_2 + 6\,	ext{H}_2	ext{O} + 38\,	ext{ATP}$$

Question 5

Which of the following statements about ATP synthase (ATPase) is TRUE?

Accepted Answer

ATP synthase uses the proton motive force to catalyze the synthesis of ATP from ADP and $$P_i.$$

Question 6

During lactic acid fermentation, what is the primary purpose of converting pyruvate to lactate?

Accepted Answer

To regenerate NAD$$^+$$ for glycolysis

Question 7

Which of the following best explains why oxidative phosphorylation conserves more energy than fermentation?

Accepted Answer

Oxidative phosphorylation fully oxidizes substrates and uses the proton motive force to generate more ATP.

Question 8

Which of the following is a key difference between aerobic and anaerobic respiration in bacteria?

Accepted Answer

Aerobic respiration uses O$$_2 as $$the terminal electron acceptor, while anaerobic respiration uses other molecules such as NO$$_3^- or SO$_4$$^{2-}$$.

Question 9

A bacterium is growing in an environment with no oxygen but abundant nitrate. Which metabolic pathway is it most likely to use for energy conservation?

Accepted Answer

Anaerobic respiration using nitrate as the terminal electron acceptor

Question 10

Which of the following best describes the role of NADH and FADH$$_2 in $$cellular respiration?

Accepted Answer

They donate electrons to the electron transport chain, facilitating ATP production.

Question 11

Which of the following is a correct statement about the Embden–Meyerhof–Parnas pathway (glycolysis)?

Accepted Answer

It converts glucose to two molecules of pyruvate, generating a net gain of 2 ATP and 2 NADH.

Question 12

Which of the following is a real-world example of a chemoorganotroph?

Accepted Answer

Escherichia coli using glucose as an energy source

Question 13

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

Accepted Answer

It generates NADH, FADH$$_2$$, and CO$$_2$$ from acetyl-CoA.

Question 14

Which of the following best explains why Paracoccus denitrificans is used as a model organism for studying respiration?

Accepted Answer

It has a respiratory chain similar to mitochondria, reflecting ancient endosymbiosis.

Question 15

Which of the following is a consequence of the separation of H$$^+$$ and OH$$^-$$ across the cytoplasmic membrane during electron transport?

Accepted Answer

Generation of a proton motive force that energizes the membrane

Question 16

Which of the following is TRUE regarding the versatility of Escherichia coli metabolism?

Accepted Answer

It can switch between aerobic respiration, anaerobic respiration, and fermentation depending on environmental conditions.

Question 17

Which of the following is a correct comparison between fermentation and anaerobic respiration?

Accepted Answer

Fermentation generates ATP by substrate-level phosphorylation, while anaerobic respiration generates ATP by oxidative phosphorylation.

Question 18

If three bacteria are competing for glucose, one capable of aerobic respiration, one of anaerobic respiration with nitrate, and one of anaerobic respiration with sulfate, which would be most competitive in an oxic environment?

Accepted Answer

The bacterium using oxygen as an electron acceptor

Microbial Metabolism: Fundamentals, Pathways, and Energy Conservation

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