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 diver climbs up a platform, converting kinetic energy to potential energy. When the diver jumps, what type of energy transformation primarily occurs as the diver falls?

Accepted Answer

Potential energy is converted to kinetic energy.

Question 3

Which of the following is an example of a catabolic pathway?

Accepted Answer

Breakdown of glucose during cellular respiration.

Question 4

According to the second law of thermodynamics, what happens during every energy transfer or transformation in biological systems?

Accepted Answer

Some energy is lost as heat, increasing entropy.

Question 5

Which equation correctly represents the change in free energy ($$\Delta G) in a $$system?

Accepted Answer

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

Question 6

Which of the following reactions is spontaneous in a biological system?

Accepted Answer

A reaction with $$\Delta G \u003c 0$$

Question 7

What is the primary role of ATP in cellular metabolism?

Accepted Answer

To provide energy for cellular work by coupling exergonic and endergonic reactions.

Question 8

During the hydrolysis of ATP, what is the free energy change ($$\Delta G) $$under standard conditions?

Accepted Answer

$$\Delta G = -7.3$$ kcal/mol

Question 9

Which process is an example of energy coupling in cells?

Accepted Answer

ATP hydrolysis driving the synthesis of glutamine from glutamic acid and ammonia.

Question 10

What is the function of enzymes in metabolic pathways?

Accepted Answer

They lower the activation energy ($$E_a) $$required for reactions.

Question 11

Which statement about enzyme-substrate specificity is correct?

Accepted Answer

Enzymes have a specific active site that binds only certain substrates.

Question 12

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the active site and blocking substrate access.

Question 13

Which of the following best describes an endergonic reaction?

Accepted Answer

It requires energy input and is nonspontaneous.

Question 14

If a cell is at equilibrium, which statement is true regarding its ability to do work?

Accepted Answer

It cannot do any work.

Question 15

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

Accepted Answer

Passive diffusion of gases.

Question 16

Which of the following statements about metabolic pathways is correct?

Accepted Answer

A specific molecule is altered in a series of defined steps, each catalyzed by a specific enzyme.

Question 17

Which of the following would increase the entropy of a system?

Accepted Answer

Breakdown of a large molecule into smaller molecules.

Question 18

What is the effect of a noncompetitive inhibitor on enzyme activity?

Accepted Answer

It binds to a different site, changing the enzyme's shape and reducing activity.

Question 19

Which of the following best explains why enzymes do not change the free energy ($$\Delta G) of a $$reaction?

Accepted Answer

Enzymes only lower the activation energy ($$E_a$$), not the overall energy change.

Question 20

A scientist dissolves sucrose in water and observes that the reaction is very slow. What is the most effective way to speed up this reaction in a biological system?

Accepted Answer

Add the enzyme sucrase to catalyze the reaction.

Chapter 8: Metabolism and Thermodynamics in Biology

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