Question 1

Which of the following best describes the type of cellular work illustrated by the process of photosynthesis in plants?

Accepted Answer

Synthetic work

Question 2

A weightlifter contracts their muscles to lift a barbell. This is an example of which type of cellular work?

Accepted Answer

Mechanical work

Question 3

Which of the following equations correctly relates the change in free energy ($$\Delta G$$), enthalpy ($$\Delta H$$), and entropy ($$\Delta S) at $$constant temperature?

Accepted Answer

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

Question 4

A reaction has $$\Delta H = -100 kJ/$$mol and $$\Delta S = +0.2 kJ/($$mol\cdot K). At $$T = 300 K$$, what is $$\Delta G$$? Is the reaction spontaneous?

Accepted Answer

$$\Delta G = -60 kJ/$$mol; spontaneous

Question 5

Which of the following best describes an exergonic reaction?

Accepted Answer

A reaction with $$\Delta G \u003c 0$$ that releases free energy

Question 6

Which of the following statements about entropy ($$\Delta S) is $$correct?

Accepted Answer

A positive $$\Delta S$$ means the system becomes less ordered

Question 7

A cell accumulates glucose against its concentration gradient. This is an example of:

Accepted Answer

Concentration work

Question 8

Which of the following is true for a reaction at equilibrium?

Accepted Answer

There is no net change in the concentrations of reactants and products

Question 9

If $$K_{eq} \u003e 1$$, what can you conclude about $$\Delta G^\circ$$ for the reaction?

Accepted Answer

$$\Delta G^\circ is $$negative

Question 10

A reaction has $$K_{eq} = 0.56. $$Under prevailing conditions, $$[P] = 15 mM $$and $$[R] = 50 mM. $$Will the forward reaction be favored to reach equilibrium?

Accepted Answer

Yes, because the product/reactant ratio is less than $$K_{eq}$$

Question 11

Which of the following best describes the role of redox reactions in cellular energy transformations?

Accepted Answer

They involve the transfer of electrons, with oxidation being the loss and reduction the gain of electrons

Question 12

Which of the following is an example of electrical work in cells?

Accepted Answer

The active transport of protons to generate a membrane potential

Question 13

Which of the following is a correct statement about the first law of thermodynamics?

Accepted Answer

Energy can be transformed from one form to another, but the total energy remains constant

Question 14

A reaction has $$\Delta H = +50 kJ/$$mol and $$\Delta S = +0.2 kJ/($$mol\cdot K). At what temperature will the reaction become spontaneous?

Accepted Answer

At temperatures above $$250 K$$

Question 15

Which of the following best explains how cells drive endergonic reactions?

Accepted Answer

By coupling them to exergonic reactions such as ATP hydrolysis

Question 16

Which of the following is a real-life example of bioluminescence?

Accepted Answer

The courtship signaling of fireflies

Question 17

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

Accepted Answer

Open systems exchange both energy and matter with their surroundings

Question 18

Which of the following best describes the change in entropy when a highly ordered system becomes more disordered?

Accepted Answer

$$\Delta S is $$positive

Question 19

Consider the oxidation of glucose: $$\Delta H = -673$$ kcal/mol, $$-T\Delta S = -13$$ kcal/mol. What is $$\Delta G$$ for this reaction?

Accepted Answer

$$\Delta G = -686$$ kcal/mol

Question 20

Which of the following best describes a chemoheterotroph?

Accepted Answer

An organism that oxidizes chemical bonds in organic molecules for energy

Bioenergetics: The Flow of Energy in the Cell

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