Question 1

Which statement best describes the First Law of Thermodynamics as it applies to biological systems?

Accepted Answer

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

Question 2

A chemical reaction in a cell releases energy and occurs spontaneously. Which type of reaction is this?

Accepted Answer

Exergonic reaction

Question 3

Which of the following best explains why enzymes are considered biological catalysts?

Accepted Answer

They lower the activation energy required for a reaction.

Question 4

A scientist adds a chemical to a reaction that binds to the active site of an enzyme, preventing substrate binding. What type of inhibitor is this?

Accepted Answer

Competitive inhibitor

Question 5

Which equation correctly represents the relationship between free energy change ($$\Delta G$$), enthalpy change ($$\Delta H$$), temperature ($$T$$), and entropy change ($$\Delta S) in a $$chemical reaction?

Accepted Answer

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

Question 6

Which of the following is true about chemical equilibrium in biological reactions?

Accepted Answer

The rate of the forward reaction equals the rate of the reverse reaction at equilibrium.

Question 7

Which process is an example of a catabolic pathway?

Accepted Answer

Breakdown of glucose during cellular respiration

Question 8

A metabolic pathway is regulated by its end product binding to an enzyme early in the pathway, inhibiting its activity. What is this regulatory mechanism called?

Accepted Answer

Feedback inhibition

Question 9

Which statement about noncompetitive inhibitors is correct?

Accepted Answer

They bind at a site remote from the active site and change the enzyme's shape.

Question 10

Which of the following best describes the Second Law of Thermodynamics in biological systems?

Accepted Answer

Every energy transfer increases the disorder (entropy) of the universe.

Question 11

Which of the following is a function of coenzymes in enzymatic reactions?

Accepted Answer

They are small nonprotein organic molecules required for enzyme function.

Question 12

Which of the following would most likely decrease the rate of an enzyme-catalyzed reaction in a cell?

Accepted Answer

Adding a noncompetitive inhibitor

Question 13

Which of the following best describes the role of activation energy in chemical reactions?

Accepted Answer

It is the energy required to start a chemical reaction.

Question 14

Which of the following statements about enzymes is FALSE?

Accepted Answer

Enzymes are destroyed during the reactions they catalyze.

Question 15

A cell is placed in an environment with a pH far from the enzyme's optimum. What is the most likely effect?

Accepted Answer

The enzyme will have decreased activity due to altered protein shape.

Question 16

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

Accepted Answer

Synthesis of glycogen from glucose molecules

Question 17

Which of the following best describes the concept of entropy ($$S) in $$biological systems?

Accepted Answer

Entropy is the measure of disorder and randomness.

Question 18

In a coupled reaction in a cell, which statement is true?

Accepted Answer

Energy released from an exergonic reaction is used to drive an endergonic reaction.

Question 19

Which of the following would most likely result from increasing the concentration of substrate in the presence of a competitive inhibitor?

Accepted Answer

The substrate will outcompete the inhibitor, increasing reaction rate.

Question 20

Which of the following is NOT a characteristic of chemical equilibrium in a reversible reaction?

Accepted Answer

The concentrations of reactants and products are always equal.

Energy Flow in the Life of a Cell: Matter, Energy, Enzymes, and Metabolism

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