Q: A cell performs a reaction with $$\Delta H = -20 kJ/$$mol and $$\Delta S = 0.05 kJ/($$mol·K)$$. If the temperature is 300$ K, what is $$\Delta G$ for the reaction?

$$\Delta G = -20 - (300 \times 0.05) = -35 kJ/$$mol

Question 1

Which of the following best describes metabolism in living organisms?

Accepted Answer

The totality of an organism’s chemical reactions, including both energy-releasing and energy-consuming pathways.

Question 2

According to the First Law of Thermodynamics, which statement is correct regarding energy in biological systems?

Accepted Answer

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

Question 3

Which equation correctly represents the change in free energy ($$\Delta G) $$for a chemical reaction at constant temperature and pressure?

Accepted Answer

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

Question 4

A reaction in a cell has $$\Delta G = -15 kJ/$$mol. What does this indicate about the reaction?

Accepted Answer

The reaction is exergonic and will occur spontaneously.

Question 5

Which of the following best explains why cells are considered open systems?

Accepted Answer

Cells constantly exchange energy and matter with their environment, preventing equilibrium.

Question 6

Which process increases the entropy ($$S) of $$the universe according to the Second Law of Thermodynamics?

Accepted Answer

Spontaneous breakdown of glucose into carbon dioxide and water.

Question 7

Which of the following is a correct comparison between catabolic and anabolic pathways?

Accepted Answer

Catabolic pathways break down complex molecules and release energy; anabolic pathways build complex molecules and consume energy.

Question 8

A cell performs a reaction with $$\Delta H = -20 kJ/$$mol and $$\Delta S = 0.05 kJ/($$mol·K)$$. If the temperature is 300$ K, what is $$\Delta G$ for the reaction?

Accepted Answer

$$\Delta G = -20 - (300 	imes 0.05) = -35 kJ/$$mol

Question 9

Which statement about spontaneous reactions is correct?

Accepted Answer

Spontaneous reactions occur without an overall input of energy and increase the entropy of the universe.

Question 10

Why do cells never reach equilibrium in their metabolic pathways?

Accepted Answer

Because equilibrium would mean no net energy change and no work could be done.

Question 11

Which of the following is an example of an endergonic reaction?

Accepted Answer

Synthesis of glucose from carbon dioxide and water during photosynthesis.

Question 12

If a reaction has $$\Delta G \u003e 0$$, what does this imply?

Accepted Answer

The reaction is endergonic and requires an input of energy.

Question 13

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

Accepted Answer

Entropy is a measure of molecular disorder or randomness.

Question 14

A cell uses ATP to drive the synthesis of proteins. Which type of reaction is this?

Accepted Answer

Endergonic reaction

Question 15

Which of the following is true about the relationship between free energy and stability in a system?

Accepted Answer

Lower free energy means greater stability.

Question 16

Which of the following is a real-life example of an exergonic reaction?

Accepted Answer

Cellular respiration in humans

Question 17

If a cell’s metabolic reactions were to reach equilibrium, what would be the consequence?

Accepted Answer

The cell would lose its ability to do work and eventually die.

Question 18

Which of the following statements about energy transfer in cells is correct?

Accepted Answer

Some energy is lost as heat during every energy transfer.

Question 19

Which of the following is NOT a characteristic of spontaneous processes in cells?

Accepted Answer

They always occur rapidly.

Question 20

Which of the following best explains why cells must manage energy and material resources?

Accepted Answer

To perform work and sustain life processes.

Introduction to Metabolism and Thermodynamics in Cells

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