Question 1

Which of the following best describes the difference between catabolic and anabolic pathways in cellular metabolism?

Accepted Answer

Catabolic pathways release energy by breaking down complex molecules into simpler compounds, while anabolic pathways consume energy to build complex molecules from simpler ones.

Question 2

A cell uses the energy released from the breakdown of glucose to synthesize ATP. Which law of thermodynamics does this process illustrate?

Accepted Answer

The first law of thermodynamics, because energy is transferred and transformed but not created or destroyed.

Question 3

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

Accepted Answer

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

Question 4

Which of the following is an example of kinetic energy in a biological system?

Accepted Answer

The movement of a cheetah chasing its prey.

Question 5

Why do living cells never reach equilibrium in their metabolic pathways?

Accepted Answer

Because cells are open systems with a constant flow of materials, preventing equilibrium.

Question 6

Which of the following statements about exergonic and endergonic reactions is correct?

Accepted Answer

Exergonic reactions release free energy and are spontaneous, while endergonic reactions absorb free energy and are nonspontaneous.

Question 7

A scientist observes that a certain reaction in a cell has $$\Delta G \u003c 0. $$What can be concluded about this reaction?

Accepted Answer

The reaction is spontaneous and can perform work.

Question 8

Which of the following best explains why the evolution of more complex organisms does not violate the second law of thermodynamics?

Accepted Answer

Because the decrease in entropy within the organism is offset by a greater increase in the entropy of the universe.

Question 9

Which of the following is a real-life example of an anabolic pathway?

Accepted Answer

The synthesis of proteins from amino acids during muscle growth.

Question 10

A hydroelectric dam is used as an analogy for cellular metabolism. In this analogy, what does the constant flow of water represent?

Accepted Answer

The constant flow of materials and energy through a living cell.

Question 11

Which of the following statements about entropy is correct?

Accepted Answer

Spontaneous processes increase the entropy of the universe.

Question 12

A reaction has $$\Delta H = -100 kJ$$, $$\Delta S = 0.2 kJ/K$$, and occurs at $$T = 300 K. $$What is $$\Delta G$$ for this reaction?

Accepted Answer

$$\Delta G = -100 - (300 	imes 0.2) = -160 kJ$$

Question 13

Which of the following best describes the role of enzymes in metabolic pathways?

Accepted Answer

Each step in a metabolic pathway is catalyzed by a specific enzyme, lowering the activation energy.

Question 14

Which of the following is an example of potential energy in a biological context?

Accepted Answer

The energy stored in the chemical bonds of ATP.

Question 15

During cellular respiration, glucose is broken down and energy is released. Which type of metabolic pathway does this represent?

Accepted Answer

Catabolic pathway

Question 16

Which of the following statements about open and closed systems is true?

Accepted Answer

Organisms are open systems because they exchange energy and matter with their environment.

Question 17

Which of the following best explains why energy conversions are never 100% efficient in biological systems?

Accepted Answer

Some energy is always lost as heat, increasing the entropy of the universe.

Question 18

A cell synthesizes a complex carbohydrate from simple sugars. What type of reaction is this, and what is the sign of $$\Delta G$$?

Accepted Answer

Anabolic reaction; $$\Delta G \u003e 0$$

Question 19

Which of the following scenarios best illustrates the second law of thermodynamics in a living system?

Accepted Answer

A muscle cell converting chemical energy into movement and releasing heat.

Question 20

Which of the following is true about spontaneous processes in biological systems?

Accepted Answer

They occur without energy input and increase the entropy of the universe.

Chapter 8 part 1

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