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 complex molecules, and anabolic pathways use that energy to build complex molecules.

Question 2

According to the first law of thermodynamics, which statement is correct regarding energy in biological systems?

Accepted Answer

Energy can be transferred and transformed, but it cannot be created or destroyed.

Question 3

A bear running releases heat to its surroundings. Which law of thermodynamics does this illustrate, and what is the consequence?

Accepted Answer

Second law; energy transfer increases the entropy of the universe.

Question 4

Which equation correctly relates the change in free energy ($$\Delta G) to $$enthalpy ($$\Delta H$$), entropy ($$\Delta S$$), and temperature ($$T$$)?

Accepted Answer

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

Question 5

A reaction has $$\Delta G = -10$$ kcal/mol. What does this indicate about the reaction?

Accepted Answer

The reaction is spontaneous and releases free energy.

Question 6

Which of the following is true about ATP hydrolysis in cells?

Accepted Answer

Energy is released from ATP hydrolysis due to the chemical change to a state of lower free energy, not from the phosphate bond itself.

Question 7

Which process describes the use of an exergonic reaction to drive an endergonic reaction in cells?

Accepted Answer

Energy coupling

Question 8

If the $$\Delta G of an $$endergonic reaction is less than the energy released by ATP hydrolysis, what can happen?

Accepted Answer

The endergonic reaction can be coupled to ATP hydrolysis and proceed.

Question 9

Which of the following statements about enzymes is correct?

Accepted Answer

Enzymes lower the activation energy ($$E_A) $$barrier, speeding up reactions.

Question 10

A competitive inhibitor affects an enzyme by:

Accepted Answer

Binding to the active site, preventing substrate binding.

Question 11

Which of the following best explains why metabolic reactions in cells do not reach equilibrium?

Accepted Answer

Cells are open systems with a constant flow of materials, preventing equilibrium.

Question 12

Which of the following is an example of feedback inhibition in a metabolic pathway?

Accepted Answer

The end product of the pathway binds to an enzyme early in the pathway, shutting it down.

Question 13

Which statement about enzyme specificity is correct?

Accepted Answer

Enzyme specificity results from the complementary fit between the substrate and the active site.

Question 14

What is the effect of increasing substrate concentration in an enzyme-catalyzed reaction when the enzyme is saturated?

Accepted Answer

The reaction rate will not increase unless more enzyme is added.

Question 15

Which of the following is a function of cofactors in enzyme activity?

Accepted Answer

Cofactors are nonprotein helpers that assist enzyme function.

Question 16

Which of the following best describes allosteric regulation?

Accepted Answer

A regulatory molecule binds to a different site, affecting the enzyme's function at the active site.

Question 17

Which scenario illustrates cooperativity in enzyme regulation?

Accepted Answer

One substrate molecule binding to an enzyme primes it to act on additional substrate molecules more readily.

Question 18

Which of the following is NOT a way that the active site of an enzyme can lower the activation energy ($$E_A) $$barrier?

Accepted Answer

Increasing the $$\Delta G of $$the reaction.

Question 19

Why is ATP considered a renewable resource in cells?

Accepted Answer

ATP is regenerated by the addition of a phosphate group to ADP, using energy from catabolic reactions.

Question 20

Which of the following best explains why living cells are considered 'islands' of low entropy?

Accepted Answer

Cells increase their internal order while increasing the disorder of their surroundings, resulting in an overall increase in entropy.

An Introduction to Metabolism: Energy, Enzymes, and Regulation in Biological Systems

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