Question 1

Which of the following best describes the Second Law of Thermodynamics as it applies to cellular metabolism?

Accepted Answer

Energy conversions increase the entropy (disorder) of the universe.

Question 2

A scientist is studying a metabolic pathway in which a complex molecule is broken down into simpler molecules, releasing energy. Which type of reaction is this, and what is the energy used for?

Accepted Answer

Catabolic reaction; energy is used to drive anabolic reactions.

Question 3

Which of the following statements about enzymes is FALSE?

Accepted Answer

Enzymes increase the activation energy required for a reaction.

Question 4

A patient is given a drug that acts as a noncompetitive inhibitor of a key metabolic enzyme. What is the most likely effect of this drug on the enzyme's activity?

Accepted Answer

It will bind to a site other than the active site, altering the enzyme's shape and reducing its activity.

Question 5

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

A high-energy phosphate from an intermediate molecule is added to ADP to form ATP.

Question 6

During glycolysis, what are the net products generated from one molecule of glucose?

Accepted Answer

2 ATP, 2 NADH, and 2 pyruvic acid

Question 7

Which of the following is TRUE regarding the electron transport chain (ETC) in aerobic respiration?

Accepted Answer

Electrons are passed through a series of carriers, and O2 is the final electron acceptor.

Question 8

A mutation causes a bacterium to lack the enzyme ATP synthase. Which process would be most directly affected?

Accepted Answer

Oxidative phosphorylation during the electron transport chain

Question 9

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

Accepted Answer

It is reduced to NADH, carrying electrons to the electron transport chain.

Question 10

In the Krebs cycle, what is the fate of the carbon atoms from acetyl-CoA?

Accepted Answer

They are released as CO2.

Question 11

Which of the following statements about fermentation is correct?

Accepted Answer

Fermentation results in the partial breakdown of sugars to organic end-products in the absence of O2.

Question 12

A researcher is studying a metabolic pathway that produces one ATP and 12 NADPH molecules from one glucose molecule. Which pathway is being studied?

Accepted Answer

Pentose Phosphate pathway

Question 13

Which of the following is a correct definition of oxidative phosphorylation?

Accepted Answer

Energy is released as electrons are passed to oxygen through a series of cytochromes in an electron transport chain.

Question 14

Which of the following best explains why increasing temperature beyond the optimum can decrease enzyme activity?

Accepted Answer

It causes denaturation, altering the enzyme's three-dimensional structure.

Question 15

In prokaryotic cells, where are the electron carriers of the electron transport chain located?

Accepted Answer

In the plasma membrane

Question 16

A cell is exposed to a competitive inhibitor. What is the most likely effect on the enzyme's activity?

Accepted Answer

The inhibitor competes with the substrate for the active site, reducing enzyme activity.

Question 17

Which of the following equations correctly represents the net ATP yield from complete aerobic respiration of one glucose molecule in prokaryotes?

Accepted Answer

$$38 \, 	ext{ATP}$$

Question 18

Which of the following is a function of the chemiosmotic mechanism in ATP generation?

Accepted Answer

It uses the energy from proton movement across a membrane to synthesize ATP from ADP and phosphate.

Question 19

Which of the following is a correct definition of anaerobic respiration?

Accepted Answer

The oxidation of organic molecules in an electron transport chain with inorganic molecules other than O2 serving as the final electron acceptor.

Question 20

A cell is using the Entner-Doudoroff pathway for glucose catabolism. What are the net products per glucose molecule?

Accepted Answer

1 ATP and 2 NADPH

Microbial Metabolism: Energy, Enzymes, and Pathways

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