Question 1

Which of the following best describes the First Law of Thermodynamics as it applies to biological systems?

Accepted Answer

Energy is transferred and transformed, but the total amount remains constant.

Question 2

A moose eats a plant and uses the chemical energy stored in the plant to move. According to the Second Law of Thermodynamics, what happens to the energy during this process?

Accepted Answer

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

Question 3

Which equation correctly represents the change in Gibbs free energy for a reaction?

Accepted Answer

$$\Delta G = G_{products} - G_{reactants}$$

Question 4

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

Accepted Answer

The reaction releases energy and is exergonic.

Question 5

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

Accepted Answer

The concentration gradient of protons across a membrane.

Question 6

During catabolic reactions, macromolecules are broken down into subunits. What is the typical $$\Delta G$$ for these reactions?

Accepted Answer

$$\Delta G is $$negative, energy is released.

Question 7

Which statement about enzymes is correct?

Accepted Answer

Enzymes lower the activation energy but do not change $$\Delta G.$$

Question 8

ATP hydrolysis releases a large amount of energy primarily because:

Accepted Answer

The phosphate groups experience electrostatic repulsion, making the bonds easy to break.

Question 9

Which of the following best describes an anabolic pathway?

Accepted Answer

It builds macromolecules from subunits, requiring energy input.

Question 10

In the context of redox reactions, which statement is true?

Accepted Answer

Reduction is the gain of electrons and is energetically unfavorable.

Question 11

A dam stores water at a high elevation. Which type of energy does this represent, and what biological analogy can be made?

Accepted Answer

Potential energy; analogous to a concentration gradient across a membrane.

Question 12

Which of the following is a consequence of the Second Law of Thermodynamics in living cells?

Accepted Answer

Cells require a constant input of energy to maintain order and decrease entropy locally.

Question 13

Which process is described by the equation $$\Delta U = Q - W$$?

Accepted Answer

First Law of Thermodynamics

Question 14

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

Accepted Answer

Some energy is always lost as heat, increasing entropy.

Question 15

Which of the following best describes the role of ATP in cellular metabolism?

Accepted Answer

ATP couples energy-releasing and energy-requiring reactions.

Question 16

Which scenario represents an exergonic reaction?

Accepted Answer

Breaking down glucose into CO$$_2$$ and H$$_2O $$with a negative $$\Delta G.$$

Question 17

Which of the following is true about enzyme-substrate interactions?

Accepted Answer

The enzyme strains substrate bonds to lower activation energy.

Question 18

Which of the following is a correct interpretation of the redox tower in cellular respiration?

Accepted Answer

The electron donor (glucose) is above the electron acceptor (oxygen), making the reaction energetically favorable.

Question 19

Which of the following best explains why repeated energy transformations in a closed system eventually result in all energy becoming unusable?

Accepted Answer

Each transformation increases entropy, converting usable energy to heat.

Question 20

Which of the following is a real-world example of energy coupling in biological systems?

Accepted Answer

The hydrolysis of ATP powers muscle contraction.

Energy, Metabolism, and Thermodynamics in Biological Systems

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