Question 1

Which of the following best describes the second law of thermodynamics as it applies to biological systems?

Accepted Answer

Every energy transfer or transformation increases the entropy of the universe.

Question 2

A metabolic pathway converts molecule A to molecule D through a series of enzyme-catalyzed steps. If enzyme 2 is inhibited, what will happen to the concentrations of molecules B and C?

Accepted Answer

B will accumulate, C will decrease.

Question 3

Which of the following equations correctly represents the change in free energy ($$\Delta G) $$for a chemical reaction?

Accepted Answer

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

Question 4

Which of the following is an example of an anabolic pathway?

Accepted Answer

The synthesis of protein from amino acids.

Question 5

A reaction has $$\Delta G = -10$$ kcal/mol. Which of the following statements is true?

Accepted Answer

The reaction is exergonic and spontaneous.

Question 6

Which of the following best explains why ATP is useful in cellular metabolism?

Accepted Answer

ATP releases energy when one of its phosphate groups is removed by hydrolysis.

Question 7

Which of the following statements about enzymes is FALSE?

Accepted Answer

Enzymes change the overall free energy change ($$\Delta G) of a $$reaction.

Question 8

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

Accepted Answer

Binding to the active site and blocking substrate entry.

Question 9

Which of the following is a correct description of energy coupling in cells?

Accepted Answer

Energy coupling uses an exergonic process to drive an endergonic one.

Question 10

Which of the following environmental factors can affect enzyme activity?

Accepted Answer

Both temperature and pH.

Question 11

Which of the following best describes the role of cofactors in enzyme activity?

Accepted Answer

Cofactors are nonprotein helpers that may be inorganic or organic.

Question 12

Which of the following is true about noncompetitive enzyme inhibitors?

Accepted Answer

They bind to a different site, changing the enzyme's shape and reducing activity.

Question 13

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

Accepted Answer

A glucose molecule with energy stored in its chemical bonds.

Question 14

Which of the following statements about spontaneous reactions is correct?

Accepted Answer

Spontaneous reactions have a negative $$\Delta G.$$

Question 15

In the hydrolysis of sucrose by sucrase, which of the following is true?

Accepted Answer

The reaction is exergonic and releases energy.

Question 16

Which of the following best explains why living organisms do not violate the second law of thermodynamics?

Accepted Answer

They increase the entropy of their surroundings through metabolism.

Question 17

Which of the following is NOT a main type of cellular work powered by ATP?

Accepted Answer

Thermal work

Question 18

A reaction has $$\Delta G = +5$$ kcal/mol. Which of the following is true?

Accepted Answer

The reaction is endergonic and requires energy input.

Question 19

Which of the following best describes the ATP cycle?

Accepted Answer

ATP is synthesized from ADP and phosphate using energy from catabolic reactions.

Question 20

Which of the following is true about the induced fit model of enzyme function?

Accepted Answer

The enzyme changes shape slightly to fit the substrate more closely.

Chapter 8: An Introduction to Metabolism – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards