Question 1

Which of the following is an example of mechanical work in a biological system?

Accepted Answer

The contraction of a weight lifter's muscles

Question 2

Which equation correctly represents the change in free energy for a system at constant temperature and pressure?

Accepted Answer

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

Question 3

A reaction has $$\Delta H = -50 kJ/$$mol and $$\Delta S = -0.1 kJ/($$mol·K). At $$T = 300 K$$, what is $$\Delta G$$ for the reaction?

Accepted Answer

$$\Delta G = -20 kJ/$$mol

Question 4

Which of the following best describes an open system in biological terms?

Accepted Answer

A plant exchanging energy and matter with its surroundings

Question 5

During the oxidation of glucose, which of the following statements is true?

Accepted Answer

Electrons are removed from glucose and transferred to oxygen

Question 6

Which type of biological work is illustrated by the movement of flagella in Chlamydomonas cells?

Accepted Answer

Mechanical work

Question 7

If a reaction has $$\Delta G \u003c 0$$, which of the following is true?

Accepted Answer

The reaction is exergonic and can occur spontaneously

Question 8

Which of the following is an example of concentration work in a cell?

Accepted Answer

Active transport of molecules to create a concentration gradient

Question 9

The first law of thermodynamics states that:

Accepted Answer

Energy cannot be created or destroyed, only transformed

Question 10

Which of the following best describes an exergonic reaction?

Accepted Answer

$$\Delta G is $$negative and energy is released

Question 11

In the biosphere, which process is responsible for converting solar energy into chemical energy?

Accepted Answer

Photosynthesis

Question 12

Which of the following is NOT a type of biological work performed by cells?

Accepted Answer

Radioactive decay

Question 13

A cell accumulates protons inside a mitochondrion, creating a charge gradient. This is an example of:

Accepted Answer

Electrical work

Question 14

Which of the following reactions is endergonic?

Accepted Answer

Synthesis of glucose from carbon dioxide and water

Question 15

Which of the following best describes the second law of thermodynamics?

Accepted Answer

The universe tends toward greater disorder (entropy)

Question 16

A firefly emits light during courtship. This is an example of which type of biological work?

Accepted Answer

Bioluminescence

Question 17

Which of the following statements about enthalpy ($$\Delta H) is $$correct?

Accepted Answer

If $$\Delta H is $$negative, the reaction releases heat and is exothermic

Question 18

Which of the following best explains why the synthesis of glucose from carbon dioxide and water is not spontaneous under standard conditions?

Accepted Answer

It has a positive $$\Delta G$$ and requires an input of energy

Question 19

Which of the following is a correct statement about the relationship between $$\Delta G$$, $$\Delta H$$, and $$\Delta S$$?

Accepted Answer

$$\Delta G$$ can be negative even if $$\Delta H is $$positive, provided $$T\Delta S is $$sufficiently positive

Question 20

Which of the following is an example of heat production as a type of biological work?

Accepted Answer

Shivering in the cold

Bioenergetics: The Flow of Energy in the Cell

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