Question 1

Which of the following best describes metabolism in living organisms?

Accepted Answer

The sum of all chemical reactions occurring within an organism.

Question 2

A metabolic pathway is characterized by which of the following?

Accepted Answer

A series of enzyme-catalyzed steps that convert a specific molecule to a product.

Question 3

Which of the following statements about catabolic and anabolic pathways is correct?

Accepted Answer

Catabolic pathways release energy by breaking down complex molecules.

Question 4

The change in free energy ($$\Delta G) $$for a reaction is given by which equation?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$

Question 5

Which of the following is true about exergonic reactions?

Accepted Answer

They proceed with a net release of free energy and are spontaneous.

Question 6

Why is metabolism in living cells never at equilibrium?

Accepted Answer

Cells are open systems with a constant flow of materials.

Question 7

ATP powers cellular work by:

Accepted Answer

Coupling exergonic reactions to endergonic reactions.

Question 8

What is released when the terminal phosphate bond of ATP is broken?

Accepted Answer

Energy

Question 9

Which statement best explains how enzymes speed up chemical reactions?

Accepted Answer

They lower the activation energy barrier.

Question 10

The specificity of an enzyme is primarily determined by:

Accepted Answer

The shape of its active site.

Question 11

Which of the following is an example of a coenzyme?

Accepted Answer

Vitamin B6

Question 12

A competitive inhibitor decreases the rate of an enzyme reaction by:

Accepted Answer

Binding to the active site and competing with the substrate.

Question 13

Allosteric regulation of enzymes involves:

Accepted Answer

Binding of a regulatory molecule to a site other than the active site.

Question 14

Feedback inhibition is important in metabolic pathways because it:

Accepted Answer

Prevents the cell from synthesizing more product than needed.

Question 15

Which of the following best describes the ATP cycle?

Accepted Answer

ATP is regenerated by adding a phosphate group to ADP using energy from catabolic reactions.

Question 16

Which of the following would most likely result if a cell's metabolic pathways were not tightly regulated?

Accepted Answer

Chemical chaos and inefficient use of resources.

Question 17

Which of the following is true regarding the effect of enzymes on the activation energy ($$E_a) $$and free energy change ($$\Delta G) of a $$reaction?

Accepted Answer

Enzymes lower $$E_a$$ but do not affect $$\Delta G.$$

Question 18

A patient is given a drug that acts as a noncompetitive inhibitor for a key metabolic enzyme. What is the most likely effect?

Accepted Answer

The enzyme's activity decreases because the inhibitor binds to a site other than the active site, altering the enzyme's shape.

Question 19

Which of the following best explains why cells require a constant supply of ATP?

Accepted Answer

ATP is used to drive many endergonic reactions necessary for cellular function.

Question 20

Which of the following is a real-life example of feedback inhibition?

Accepted Answer

The end product of the pathway for isoleucine synthesis inhibits the first enzyme in the pathway.

Metabolism and Energy: Foundations of Cellular Processes

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