Question 1

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

Accepted Answer

Entropy (disorder) increases in spontaneous processes, so living organisms must use energy to maintain order.

Question 2

A reaction has a negative change in free energy ($$\Delta G \u003c 0). $$Which of the following statements is TRUE about this reaction?

Accepted Answer

It is exergonic and occurs spontaneously.

Question 3

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

Accepted Answer

A molecule of ATP storing energy in its phosphate bonds.

Question 4

A scientist adds a non-competitive inhibitor to an enzyme-catalyzed reaction. What is the most likely effect?

Accepted Answer

The inhibitor binds elsewhere, changing the enzyme's shape and reducing activity.

Question 5

Which of the following best explains why ATP is considered the 'universal energy currency' in cells?

Accepted Answer

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

Question 6

A metabolic pathway is regulated by feedback inhibition. Which of the following best describes this process?

Accepted Answer

The end product of the pathway inhibits the first enzyme, preventing overproduction.

Question 7

Which of the following would most likely increase the rate of an enzyme-catalyzed reaction, assuming all other factors are optimal?

Accepted Answer

Increasing the concentration of substrate up to the point of enzyme saturation.

Question 8

Which statement about anabolic and catabolic reactions is correct?

Accepted Answer

Anabolic reactions build complex molecules and are endergonic, while catabolic reactions break down molecules and are exergonic.

Question 9

A patient has a genetic mutation that prevents the production of a necessary coenzyme for a key metabolic enzyme. What is the most likely consequence?

Accepted Answer

The enzyme's activity will decrease or stop, impairing the metabolic pathway.

Question 10

Which of the following best describes the role of activation energy ($$E_a) in a $$chemical reaction?

Accepted Answer

It is the minimum energy required to start a reaction and reach the transition state.

Question 11

If a reaction has $$\Delta G \u003e 0$$, which of the following is true?

Accepted Answer

The reaction is endergonic and requires energy input.

Question 12

Which of the following scenarios best illustrates the concept of entropy ($$S) in a $$biological system?

Accepted Answer

A drop of dye dispersing evenly in a beaker of water, increasing disorder.

Question 13

Which of the following is NOT a way that enzymes lower the activation energy of a reaction?

Accepted Answer

Increasing the temperature of the reaction.

Question 14

A researcher observes that increasing the concentration of substrate no longer increases the rate of an enzyme-catalyzed reaction. What is the most likely explanation?

Accepted Answer

The enzyme is saturated; all active sites are occupied.

Question 15

Which of the following best describes the effect of a competitive inhibitor on an enzyme?

Accepted Answer

It binds to the active site, blocking substrate binding.

Question 16

Which of the following is a real-life example of an exergonic reaction in human cells?

Accepted Answer

Hydrolysis of ATP to ADP and inorganic phosphate.

Question 17

A metabolic pathway is regulated by phosphorylation of the first enzyme. What is the most likely effect of phosphorylation?

Accepted Answer

It can either activate or deactivate the enzyme, depending on the specific enzyme and pathway.

Question 18

Which of the following statements about enzyme specificity is correct?

Accepted Answer

Enzymes have active sites that are specific to particular substrates.

Question 19

A cell needs to rapidly increase the rate of a metabolic reaction. Which of the following would be the most effective strategy?

Accepted Answer

Increase the amount of enzyme present.

Question 20

Which of the following best explains why living organisms do not violate the Second Law of Thermodynamics?

Accepted Answer

They maintain order internally by increasing entropy in their surroundings, using energy (e.g., from ATP).

Energy, Enzymes, and Metabolism: Core Concepts in General Biology

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