Question 1

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

Accepted Answer

Catabolic pathways release energy by breaking down complex molecules, while anabolic pathways consume energy to build complex molecules.

Question 2

A runner uses the chemical energy stored in glucose to power muscle contraction during a race. According to the first law of thermodynamics, what happens to the energy in this process?

Accepted Answer

The energy is transformed from chemical energy to kinetic and heat energy, but the total amount of energy remains constant.

Question 3

Which of the following reactions is most likely to be spontaneous in a biological system?

Accepted Answer

A reaction with $$\Delta G \u003c 0$$

Question 4

Which statement about ATP is correct?

Accepted Answer

ATP is a renewable resource that is regenerated by the addition of a phosphate group to ADP.

Question 5

A cell is placed in a closed system with no exchange of materials. What will eventually happen to the cell’s metabolic reactions?

Accepted Answer

They will stop because $$\Delta G = 0 at $$equilibrium.

Question 6

Which of the following best explains why enzymes are necessary for metabolic reactions?

Accepted Answer

Enzymes lower the activation energy ($$E_a) $$required for reactions to proceed.

Question 7

Which of the following is an example of potential energy in a biological system?

Accepted Answer

A molecule of glucose before it is metabolized

Question 8

A competitive inhibitor affects an enzyme-catalyzed reaction by:

Accepted Answer

Binding reversibly to the active site, preventing substrate binding, but can be overcome by increasing substrate concentration

Question 9

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

Accepted Answer

The end product of the pathway acts as an allosteric inhibitor of an early enzyme in the pathway.

Question 10

If the hydrolysis of ATP to ADP and $$P_i$$ has $$\Delta G = -7.3$$ kcal/mol, what does this indicate about the reaction?

Accepted Answer

It is an exergonic reaction that releases energy.

Question 11

Which of the following scenarios best illustrates the second law of thermodynamics in a biological context?

Accepted Answer

A bear eating a fish and releasing heat as it runs.

Question 12

Which of the following is NOT a way that enzymes lower activation energy ($$E_a$$)?

Accepted Answer

Increasing the free energy of the products

Question 13

A metabolic pathway is regulated by allosteric inhibition. Which of the following is most likely to occur if the end product accumulates?

Accepted Answer

The end product will bind to a regulatory site on an early enzyme, decreasing pathway activity.

Question 14

Which of the following best describes the relationship between free energy ($$G$$), stability, and work capacity in a system?

Accepted Answer

Higher $$G$$ means less stability and greater work capacity.

Question 15

Which of the following is a real-life example of an exergonic reaction?

Accepted Answer

Hydrolysis of ATP to ADP and $$P_i$$

Question 16

Which of the following statements about entropy is correct?

Accepted Answer

Processes that increase entropy are spontaneous and energetically favorable.

Question 17

A noncompetitive inhibitor affects an enzyme-catalyzed reaction by:

Accepted Answer

Binding to a site other than the active site, decreasing the maximum reaction rate, and cannot be overcome by increasing substrate concentration.

Question 18

Which of the following best explains why living systems are described as 'islands of low entropy'?

Accepted Answer

They maintain order and low entropy by continuously using energy to counteract the natural tendency toward disorder.

Question 19

Which of the following is an example of energy coupling in cellular metabolism?

Accepted Answer

The use of ATP hydrolysis to drive the synthesis of a polymer from monomers.

Question 20

Which of the following would most likely happen if a cell’s supply of ATP was suddenly depleted?

Accepted Answer

Cellular work such as active transport and muscle contraction would rapidly decrease.

Chapter 8: An Introduction to Metabolism – Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard