Question 1

Which of the following best describes the difference between catabolic and anabolic pathways in cellular metabolism?

Accepted Answer

Catabolic pathways release energy by breaking down complex molecules, while anabolic pathways consume energy to build complex molecules.

Question 2

A cell converts glucose to carbon dioxide and water, releasing energy in the process. Which law of thermodynamics does this transformation best illustrate?

Accepted Answer

The first law of thermodynamics, which states that energy cannot be created or destroyed.

Question 3

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

Accepted Answer

The movement of ions across a membrane during nerve impulse transmission.

Question 4

According to the second law of thermodynamics, what happens to the entropy of a system as it undergoes a spontaneous chemical reaction?

Accepted Answer

Entropy increases as the system becomes more disordered.

Question 5

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 6

A reaction has $$\Delta G = -30 kJ/$$mol. What does this indicate about the reaction?

Accepted Answer

The reaction is exergonic and will occur spontaneously.

Question 7

Which of the following statements about ATP is correct?

Accepted Answer

ATP contains three phosphate groups, and hydrolysis of the terminal phosphate releases energy.

Question 8

How does ATP hydrolysis drive energetically unfavorable reactions in cells?

Accepted Answer

By coupling the hydrolysis of ATP ($$\Delta G \u003c 0) to $$the unfavorable reaction, making the overall $$\Delta G$$ negative.

Question 9

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

Accepted Answer

Enzymes lower the activation energy, allowing reactions to proceed more rapidly.

Question 10

A mutation changes the shape of an enzyme's active site. What is the most likely consequence?

Accepted Answer

The enzyme will lose its substrate specificity and may not function properly.

Question 11

Which of the following statements about enzyme regulation is correct?

Accepted Answer

Enzyme activity can be regulated by inhibitors that bind to the active site or allosteric sites.

Question 12

In a metabolic pathway, the product of one reaction inhibits an earlier enzyme in the pathway. This is an example of:

Accepted Answer

Feedback inhibition.

Question 13

Which of the following best explains why enzymes are highly specific for their substrates?

Accepted Answer

The active site of an enzyme has a unique shape that fits only specific substrate molecules.

Question 14

Which of the following is true about the relationship between substrate concentration and enzyme activity?

Accepted Answer

Enzyme activity increases with substrate concentration until the enzyme becomes saturated.

Question 15

A scientist measures the free energy change ($$\Delta G) $$for a reaction and finds it to be positive. What does this imply about the reaction?

Accepted Answer

The reaction is endergonic and requires an input of energy.

Question 16

Which of the following is NOT a form of energy transformation commonly found in biological systems?

Accepted Answer

Nuclear energy released during cellular respiration.

Question 17

Which of the following scenarios best illustrates the concept of activation energy in a chemical reaction?

Accepted Answer

A match must be struck to ignite wood, even though burning wood is exergonic.

Question 18

Which of the following best describes how enzymes affect the rate of a chemical reaction?

Accepted Answer

Enzymes lower the activation energy, speeding up the reaction.

Question 19

A patient is diagnosed with a genetic disorder that affects the structure of ATP synthase. Which cellular process is most likely to be impaired?

Accepted Answer

Cellular respiration and ATP production.

Question 20

Which of the following statements about the coupling of reactions in cells is correct?

Accepted Answer

Energetically unfavorable reactions are driven by coupling them to ATP hydrolysis, making the overall $$\Delta G$$ negative.

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

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