Question 1

Which statement best describes the relationship between the first and second laws of thermodynamics in biological systems?

Accepted Answer

The first law states that energy can be transferred or transformed but not created or destroyed, while the second law states that every energy transfer increases the entropy of the universe.

Question 2

A bear eats a fish and uses the energy to run. According to the laws of thermodynamics, what happens to the energy from the fish?

Accepted Answer

Some energy is converted to kinetic energy, and some is lost as heat, increasing entropy.

Question 3

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

Accepted Answer

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

Question 4

A reaction has $$\Delta G = -5$$ kcal/mol. What does this indicate about the reaction?

Accepted Answer

The reaction is exergonic and occurs spontaneously.

Question 5

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

Accepted Answer

ATP couples exergonic and endergonic reactions, providing energy for cellular work.

Question 6

What happens during the hydrolysis of ATP?

Accepted Answer

ATP is converted to ADP and an inorganic phosphate, releasing energy.

Question 7

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

Accepted Answer

The synthesis of protein from amino acids.

Question 8

In a metabolic pathway, what is the function of enzymes?

Accepted Answer

Enzymes speed up specific reactions by lowering the activation energy barrier.

Question 9

Which of the following statements about enzyme specificity is correct?

Accepted Answer

Enzymes recognize their specific substrate due to the complementary fit between the active site and substrate.

Question 10

A competitive inhibitor affects an enzyme by:

Accepted Answer

Binding to the active site and blocking substrate entry.

Question 11

Which of the following best describes feedback inhibition in a metabolic pathway?

Accepted Answer

The end product of the pathway inhibits an enzyme earlier in the pathway, preventing overproduction.

Question 12

Which of the following is true about the ATP cycle in cells?

Accepted Answer

ATP is regenerated from ADP by the addition of a phosphate group using energy from catabolic reactions.

Question 13

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

Accepted Answer

A plant converting light energy to chemical energy during photosynthesis.

Question 14

Which statement about exergonic and endergonic reactions is correct?

Accepted Answer

Exergonic reactions release energy and have $$\Delta G \u003c 0.$$

Question 15

Which factor does NOT affect enzyme activity?

Accepted Answer

The color of the enzyme

Question 16

What is the main purpose of allosteric regulation in enzymes?

Accepted Answer

To regulate enzyme activity by binding regulatory molecules at sites other than the active site.

Question 17

Which of the following is an example of a cofactor?

Accepted Answer

A metal ion such as zinc or iron that assists enzyme function.

Question 18

Why is heat not a practical way to speed up reactions in cells?

Accepted Answer

Heat can cause proteins to denature and speeds up all reactions indiscriminately.

Question 19

Which of the following best explains why metabolic reactions in living cells do not reach equilibrium?

Accepted Answer

Cells are open systems, allowing a constant flow of materials in and out, preventing equilibrium.

Chapter 8: An Introduction to Metabolism – Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard