Question 1

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

Accepted Answer

Energy is transferred and transformed, but the total energy in the universe remains constant.

Question 2

A firefly produces light through a chemical reaction in its body. This is an example of which biological process?

Accepted Answer

Bioluminescence

Question 3

Which of the following best explains why cells are considered open systems in terms of energy transformation?

Accepted Answer

Cells exchange both energy and matter with their surroundings, allowing a constant flow of materials and energy.

Question 4

Which equation correctly represents the change in free energy ($$\Delta G) $$for a chemical reaction?

Accepted Answer

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

Question 5

During cellular respiration, glucose is broken down into carbon dioxide and water, releasing energy. This process is an example of which type of metabolic pathway?

Accepted Answer

Catabolic pathway

Question 6

Which of the following statements about spontaneous processes is correct?

Accepted Answer

Spontaneous processes occur without energy input and increase the entropy of the universe.

Question 7

A reaction has $$\Delta G = +5$$ kcal/mol. Which of the following is true about this reaction?

Accepted Answer

It is endergonic and requires an input of energy to proceed.

Question 8

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

Accepted Answer

Enzymes act as catalysts, lowering the activation energy and speeding up reactions.

Question 9

Which statement about the Second Law of Thermodynamics is most accurate in the context of living organisms?

Accepted Answer

Every energy transfer or transformation increases the entropy of the universe.

Question 10

Which of the following is an example of an anabolic pathway?

Accepted Answer

The synthesis of proteins from amino acids at the ribosome.

Question 11

A cell is performing work by moving ions against their concentration gradient. Which form of energy is primarily being used?

Accepted Answer

Potential energy

Question 12

Which of the following best explains why equilibrium is never reached in a living cell?

Accepted Answer

Cells constantly experience a flow of materials and energy, maintaining a state far from equilibrium.

Question 13

Which of the following reactions is exergonic?

Accepted Answer

A reaction with $$\Delta G \u003c 0$$

Question 14

In a metabolic pathway, which of the following is true about the role of enzymes?

Accepted Answer

Each step is catalyzed by a specific enzyme.

Question 15

Which of the following best describes the relationship between free energy and stability in a system?

Accepted Answer

Lower free energy means the system is more stable.

Question 16

Which process in cells is most directly powered by ATP hydrolysis?

Accepted Answer

Active transport of ions across membranes

Question 17

A chemical reaction in a cell has $$\Delta G = 0. $$What does this indicate about the reaction?

Accepted Answer

The reaction is at equilibrium and cannot perform work.

Question 18

Which of the following is a correct statement about catabolic and anabolic pathways?

Accepted Answer

Catabolic pathways release energy by breaking down molecules; anabolic pathways consume energy to build molecules.

Question 19

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

Accepted Answer

Nuclear energy

Question 20

If a reaction in a cell is nonspontaneous, what must occur for the reaction to proceed?

Accepted Answer

Energy must be supplied to the system.

Energy, Activation Energy, and Enzymes: Foundations of Metabolism and Thermodynamics in Biology

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