Question 1

Which statement best describes the First Law of Thermodynamics as it applies to living cells?

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 increases the substrate concentration in an enzymatic reaction, but the reaction rate does not increase. Which type of inhibitor is most likely present?

Accepted Answer

Noncompetitive 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 an example of an anabolic pathway?

Accepted Answer

Photosynthesis building glucose from carbon dioxide and water

Question 7

What is the role of the active site in an enzyme?

Accepted Answer

It is the region where the substrate binds and the reaction occurs.

Question 8

Which statement about feedback inhibition is correct?

Accepted Answer

It regulates a metabolic pathway by the end product inhibiting an enzyme within the pathway.

Question 9

A cell is placed in an environment where the temperature is much higher than its enzyme's optimum. What is the most likely effect on enzyme activity?

Accepted Answer

Enzyme activity will decrease due to denaturation.

Question 10

Which of the following best describes a coupled reaction in biological systems?

Accepted Answer

A reaction that requires energy is paired with a reaction that releases energy.

Question 11

Which property of enzymes allows them to be substrate-specific?

Accepted Answer

The shape, size, and binding ability of the active site

Question 12

Which of the following is true about chemical equilibrium in a reversible reaction?

Accepted Answer

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

Question 13

Which of the following statements about entropy is correct?

Accepted Answer

Entropy is the measure of disorder or randomness.

Question 14

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Competing with the substrate for the active site.

Question 15

Which of the following is NOT a function of metabolism in living cells?

Accepted Answer

Destruction of enzymes after each reaction

Question 16

Which statement best describes the effect of noncompetitive inhibitors on enzyme activity?

Accepted Answer

They bind away from the active site and change its shape, reducing enzyme activity.

Question 17

Which of the following is true about coenzymes?

Accepted Answer

They are small nonprotein organic molecules required for proper enzyme catalysis.

Question 18

Which of the following reactions is energetically uphill and requires an energy source?

Accepted Answer

Endergonic reaction

Question 19

If a cell's enzyme has a pH optimum of 7.4, what would likely happen if the pH drops to 5?

Accepted Answer

Enzyme activity would decrease due to altered protein shape.

Question 20

Which of the following best describes catabolic pathways?

Accepted Answer

They release energy by breaking down complex molecules into simpler compounds.

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

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