Question 1

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

Accepted Answer

Catabolic pathways release energy by breaking down molecules, which is then used by anabolic pathways to build new molecules.

Question 2

A scientist observes that an enzyme-catalyzed reaction proceeds much more slowly at pH 4 than at pH 7. What is the most likely explanation for this observation?

Accepted Answer

The enzyme has denatured due to the acidic environment, altering its active site.

Question 3

Which of the following statements about ATP is correct?

Accepted Answer

ATP is composed of adenine, ribose, and three phosphate groups.

Question 4

During aerobic respiration, what is the final electron acceptor in the electron transport chain?

Accepted Answer

Oxygen ($$O_2)$$

Question 5

Which of the following best explains why enzymes increase the rate of chemical reactions?

Accepted Answer

They lower the activation energy by stabilizing the transition state.

Question 6

A bacterial cell is placed in an environment with a high concentration of substrate for a particular enzyme. What will happen when all enzyme active sites are occupied?

Accepted Answer

The reaction rate will reach a maximum and plateau (enzyme saturation).

Question 7

Which of the following is a correct description of substrate-level phosphorylation?

Accepted Answer

ATP is produced directly by transferring a phosphate group from a pathway intermediate to ADP.

Question 8

Which metabolic pathway is shared by aerobic respiration, anaerobic respiration, and fermentation?

Accepted Answer

Glycolysis

Question 9

A patient’s muscle cells are deprived of oxygen during intense exercise. Which metabolic process allows these cells to continue producing ATP?

Accepted Answer

Homolactic fermentation

Question 10

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

Accepted Answer

They serve as electron carriers, donating electrons to the electron transport chain.

Question 11

Which of the following is a product of the intermediate step (bridge step) between glycolysis and the Krebs cycle?

Accepted Answer

Acetyl-CoA

Question 12

A bacterium is found to be oxidase positive. What does this indicate about its metabolism?

Accepted Answer

It uses cytochrome c oxidase in its electron transport chain.

Question 13

Which of the following statements about fermentation is correct?

Accepted Answer

Fermentation regenerates $$NAD^+$$ from $$NADH to $$allow glycolysis to continue.

Question 14

Which enzyme is responsible for breaking down triglycerides into glycerol and fatty acids?

Accepted Answer

Lipase

Question 15

A microbe is classified as a chemolithotroph. What does this mean about its metabolism?

Accepted Answer

It uses inorganic molecules as a source of electrons for reducing power.

Question 16

Which of the following best describes feedback inhibition in metabolic pathways?

Accepted Answer

The end product of a pathway inhibits an enzyme early in the pathway.

Question 17

Which of the following is a distinguishing feature of mixed acid fermentation?

Accepted Answer

It produces a variety of acidic end products, such as lactic, acetic, and succinic acids.

Question 18

Which of the following best explains why reduction is the term used to describe the gain of electrons?

Accepted Answer

The net charge of the electron acceptor decreases.

Question 19

A bacterium is grown in a medium containing protein, a single carbohydrate, a pH indicator, and a Durham tube. After incubation, the medium turns yellow and gas is present in the Durham tube. What does this indicate?

Accepted Answer

The bacterium ferments the carbohydrate, producing acid and gas.

Question 20

Which of the following best describes the process of chemiosmosis in the electron transport chain?

Accepted Answer

Protons flow through ATP synthase from high to low concentration, driving the phosphorylation of ADP to ATP.

Microbial Metabolism: Pathways, Enzymes, and Energy Production

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