Question 1

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

Accepted Answer

Energy cannot be created or destroyed, only transformed or transferred.

Question 2

A cell is considered an open system because:

Accepted Answer

It exchanges both matter and energy with its surroundings.

Question 3

Which equation correctly represents the relationship between Gibbs Free Energy ($$\Delta G$$), enthalpy ($$\Delta H$$), entropy ($$\Delta S$$), and temperature ($$T$$)?

Accepted Answer

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

Question 4

A chemical reaction in a cell has $$\Delta G = -20 kJ/$$mol. What does this indicate about the reaction?

Accepted Answer

The reaction is spontaneous and can perform work.

Question 5

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

Accepted Answer

Entropy is a measure of molecular disorder or randomness.

Question 6

Consider the reaction: $$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O. If$$ $$\Delta G = -686$$ kcal/mol, what does this value tell you about cellular respiration?

Accepted Answer

Cellular respiration releases a large amount of free energy.

Question 7

Which of the following best explains why living organisms cannot be closed systems?

Accepted Answer

They would eventually reach equilibrium and stop functioning.

Question 8

According to Le Chatelier's Principle, what happens if the concentration of reactants in a reversible reaction is increased?

Accepted Answer

The reaction will shift to produce more products.

Question 9

Which formula is used to calculate the change in free energy ($$\Delta G) $$under non-standard conditions?

Accepted Answer

$$\Delta G = \Delta G^\circ + RT \ln Q$$

Question 10

Which of the following is NOT a type of energy relevant to biological systems?

Accepted Answer

Magnetic energy

Question 11

A metabolic pathway in a cell is prevented from reaching equilibrium. Why is this important for life?

Accepted Answer

Equilibrium would result in no net change and halt cellular processes.

Question 12

Which of the following statements about spontaneous reactions is true?

Accepted Answer

Spontaneous reactions have $$\Delta G \u003c 0$$ and can occur without energy input.

Question 13

If a reaction has $$\Delta H \u003e 0$$ and $$\Delta S \u003c 0$$, what can you conclude about $$\Delta G at $$all temperatures?

Accepted Answer

$$\Delta G$$ will always be positive and the reaction will be non-spontaneous.

Question 14

Which of the following best describes metabolism in living organisms?

Accepted Answer

Metabolism is the sum of all chemical reactions occurring in a living organism.

Question 15

Which of the following is a consequence of the Second Law of Thermodynamics for living systems?

Accepted Answer

Living systems can decrease entropy locally, but only by increasing entropy in their surroundings.

Question 16

Which of the following is true about chemical reactions in biological systems?

Accepted Answer

Most reactions are reversible and move toward a dynamic equilibrium.

Question 17

A student mixes glucose and oxygen in a sealed container at standard conditions. Which equation best predicts the change in free energy for the reaction?

Accepted Answer

$$\Delta G = \Delta G^\circ + RT \ln Q$$

Question 18

Which of the following statements about the pH scale is correct?

Accepted Answer

A solution with [H$$^+$$] = [OH$$^-$$] has a pH of 7.

Question 19

Which of the following is a correct statement about the conservation of mass in chemical reactions?

Accepted Answer

Atoms are neither created nor destroyed during chemical reactions.

Question 20

Which of the following best explains why the change in free energy ($$\Delta G) $$depends on the concentrations of reactants and products in living systems?

Accepted Answer

Because $$\Delta G is $$calculated using the reaction quotient $$Q$$, which reflects current concentrations.

Energy, Thermodynamics, and Metabolism in Biological Systems

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