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 it cannot be created or destroyed.

Question 2

A cell is performing the hydrolysis of ATP to power muscle contraction. Which type of work is this an example of?

Accepted Answer

Mechanical work

Question 3

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

Accepted Answer

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

Question 4

Which process is most likely to occur spontaneously in a cell according to the second law of thermodynamics?

Accepted Answer

A reaction that releases energy and increases entropy.

Question 5

An enzyme catalyzes a reaction by:

Accepted Answer

Lowering the activation energy barrier without affecting $$\Delta G.$$

Question 6

Which of the following best describes feedback inhibition in metabolic pathways?

Accepted Answer

The end product of a pathway inhibits an enzyme earlier in the pathway.

Question 7

A noncompetitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to another part of the enzyme, changing its shape and reducing activity.

Question 8

Which statement about ATP is correct?

Accepted Answer

ATP releases energy when a phosphate group is removed by hydrolysis.

Question 9

A cell is placed in a closed system and reaches equilibrium. What happens to its ability to perform work?

Accepted Answer

It decreases because no free energy is available for work.

Question 10

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

Accepted Answer

The synthesis of protein from amino acids.

Question 11

Which factor would most likely increase the rate of an enzyme-catalyzed reaction?

Accepted Answer

Increasing substrate concentration when the enzyme is not saturated.

Question 12

Which statement about cofactors is true?

Accepted Answer

Cofactors are nonprotein molecules that help enzymes function.

Question 13

If a cell's temperature increases above the optimal range for its enzymes, what is the most likely effect?

Accepted Answer

Enzyme activity will decrease due to denaturation.

Question 14

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

Accepted Answer

Cells increase entropy in their surroundings as they create order internally.

Question 15

Which of the following is true about exergonic reactions?

Accepted Answer

They release free energy and occur spontaneously.

Question 16

A scientist measures the change in enthalpy ($$\Delta H) $$and entropy ($$\Delta S) $$for a reaction at temperature $$T. $$Which formula should they use to calculate the change in free energy?

Accepted Answer

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

Question 17

Which of the following is an example of allosteric regulation of an enzyme?

Accepted Answer

A regulatory molecule binds to a site other than the active site, changing enzyme activity.

Question 18

Which statement about equilibrium in metabolism is correct?

Accepted Answer

Cells are open systems and avoid equilibrium to maintain a constant flow of materials.

Question 19

Which of the following would most likely result from a mutation that alters the active site of an enzyme?

Accepted Answer

The enzyme's substrate specificity may change.

Question 20

Which of the following is NOT a function of ATP in cells?

Accepted Answer

Serving as a catalyst for metabolic reactions.

Energy, Metabolism, and Enzyme Function in General Biology

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