NAD\textsuperscript{+} is a coenzyme that transfers electrons from glycolysis and the Krebs cycle to the electron transport chain.

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

Question 1

Which of the following statements best describes the role of NAD	extsuperscript{+} in cellular respiration?

Accepted Answer

NAD	extsuperscript{+} is a coenzyme that transfers electrons from glycolysis and the Krebs cycle to the electron transport chain.

Question 2

What is the overall chemical equation for aerobic respiration in prokaryotes?

Accepted Answer

$$C_6H_{12}O_6$ + 6O_2 + 38ADP + 38P_i \rightarrow 6CO_2 + 6H_2O + 38ATP$$

Question 3

During which step of aerobic respiration is the majority of ATP produced, and why?

Accepted Answer

Electron transport chain, because it uses the energy from NADH and FADH	extsubscript{2} to drive oxidative phosphorylation.

Question 4

Which of the following is NOT a difference between aerobic and anaerobic respiration?

Accepted Answer

Anaerobic respiration does not involve the electron transport chain.

Question 5

A bacterium is found to produce lactic acid as a major metabolic product. Which metabolic pathway is most likely being used?

Accepted Answer

Lactic acid fermentation

Question 6

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

Accepted Answer

Fermentation does not use the Krebs cycle or electron transport chain.

Question 7

Which of the following is a correct description of the final electron acceptor in fermentation?

Accepted Answer

An organic molecule such as pyruvate or its derivatives

Question 8

Which metabolic classification do most bacteria belong to?

Accepted Answer

Chemoheterotrophs

Question 9

What is the main purpose of the Calvin-Benson cycle in photosynthesis?

Accepted Answer

To fix carbon dioxide into organic molecules

Question 10

Which of the following equations represents oxygenic photosynthesis?

Accepted Answer

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

Question 11

A patient’s muscle cells are deprived of oxygen during intense exercise. Which metabolic pathway will predominate and what is the main product?

Accepted Answer

Lactic acid fermentation; lactic acid

Question 12

Which of the following is a function of coenzymes in cellular respiration?

Accepted Answer

They transfer electrons between metabolic pathways.

Question 13

Which of the following statements about glycolysis is TRUE?

Accepted Answer

Glycolysis produces pyruvic acid and a net gain of 2 ATP per glucose molecule.

Question 14

Which of the following is an example of a chemoautotroph?

Accepted Answer

Iron-oxidizing bacteria

Question 15

What would happen to an enzyme if the temperature rises significantly above its optimal range?

Accepted Answer

The enzyme would denature and lose its activity.

Question 16

Which of the following is a correct comparison between catabolism and anabolism?

Accepted Answer

Catabolism breaks down molecules to release energy, while anabolism builds complex molecules using energy.

Question 17

Which of the following is a product of the light-dependent reactions of photosynthesis?

Accepted Answer

ATP

Question 18

A noncompetitive inhibitor affects an enzyme by:

Accepted Answer

Binding to an allosteric site, changing the enzyme’s shape and reducing its activity.

Question 19

Which of the following is an industrial benefit of fermentation?

Accepted Answer

Production of ethanol and lactic acid for food and beverages

Question 20

Which of the following best describes the role of ATP in metabolism?

Accepted Answer

ATP acts as an intermediate, transferring energy from catabolic to anabolic reactions.

Microbial Metabolism: Carbohydrate Catabolism and Energy Pathways

Study Guide - Practice Questions