Question 1

Which of the following best describes the relationship between catabolic and anabolic reactions in cellular metabolism?

Accepted Answer

Catabolic reactions release energy by breaking down molecules, and this energy is used by anabolic reactions to build new molecules.

Question 2

A scientist is studying a metabolic pathway in which glucose is broken down into pyruvate, producing a net gain of 2 ATP and 2 NADH per glucose molecule. Which pathway is being described?

Accepted Answer

Glycolysis

Question 3

Which of the following statements about ATP is correct?

Accepted Answer

ATP is recharged from ADP by phosphorylation, often using energy from catabolic reactions.

Question 4

Which of the following best explains why enzymes are necessary for cellular metabolism?

Accepted Answer

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

Question 5

A patient’s muscle cells are deprived of oxygen during intense exercise. Which metabolic pathway will their cells rely on to continue producing ATP, and what is the main end product?

Accepted Answer

Homolactic fermentation; lactic acid

Question 6

Which of the following is a correct summary of the overall reaction for aerobic cellular respiration in prokaryotes?

Accepted Answer

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

Question 7

Which of the following best describes the role of NAD+ in cellular respiration?

Accepted Answer

It is a coenzyme that carries electrons from catabolic reactions to the electron transport chain.

Question 8

A bacterial culture is tested with the oxidase test and produces a blue color. What does this indicate about the bacterium?

Accepted Answer

It possesses cytochrome c oxidase and is likely to use aerobic respiration.

Question 9

Which of the following statements about enzyme inhibition is correct?

Accepted Answer

Competitive inhibitors compete with the substrate for the active site, while noncompetitive inhibitors bind elsewhere and change enzyme shape.

Question 10

Which of the following best explains why high temperatures can be detrimental to enzyme activity?

Accepted Answer

High temperatures can denature enzymes, disrupting their three-dimensional structure and rendering them inactive.

Question 11

Which of the following is a key difference between fermentation and anaerobic respiration?

Accepted Answer

Fermentation occurs in the cytoplasm and does not use a respiratory chain, while anaerobic respiration uses a membrane-associated respiratory chain.

Question 12

A microbe is classified as a chemolithoautotroph. Which of the following best describes its metabolic strategy?

Accepted Answer

It uses inorganic chemicals as an energy source and fixes carbon dioxide to make organic molecules.

Question 13

Which of the following best describes the function of ATP synthase in the electron transport chain?

Accepted Answer

It uses the energy from flowing protons to phosphorylate ADP to ATP.

Question 14

Which of the following is a correct statement about the pentose phosphate pathway?

Accepted Answer

It converts five-carbon sugars into intermediates that can enter glycolysis and produces NADPH for anabolic reactions.

Question 15

A bacterium is found to secrete lipases and proteases into its environment. What is the most likely function of these enzymes?

Accepted Answer

To break down large macromolecules outside the cell so their components can be transported into the cell for catabolism.

Question 16

Which of the following best describes feedback inhibition in a metabolic pathway?

Accepted Answer

The end product of a pathway inhibits an enzyme early in the pathway, slowing or stopping further production.

Question 17

Which of the following is a correct pairing of enzyme class and reaction catalyzed?

Accepted Answer

Hydrolase: Addition of water to break bonds

Question 18

A patient’s blood sample is tested for catalase activity. Bubbles form when hydrogen peroxide is added. What does this indicate?

Accepted Answer

The sample contains an organism that produces catalase, which breaks down hydrogen peroxide into water and oxygen.

Question 19

Which of the following best explains why the Entner-Doudoroff pathway is important in microbiology?

Accepted Answer

It is found primarily in Gram-negative obligate aerobes and produces NADPH for biosynthetic reactions.

Microbial Metabolism: Principles and Applications

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