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, whereas anabolic pathways consume energy to build complex molecules.

Question 2

A person eats a meal containing carbohydrates, which are then broken down to glucose and used to generate ATP. Which sequence of energy transformations best describes this process?

Accepted Answer

Chemical energy in carbohydrates → chemical energy in ATP → thermal energy as heat

Question 3

Which of the following is an example of increasing entropy in a biological system?

Accepted Answer

The hydrolysis of ATP to ADP and inorganic phosphate

Question 4

According to the second law of thermodynamics, how do living organisms maintain order within their cells?

Accepted Answer

By increasing the entropy of their surroundings while maintaining or decreasing their own internal entropy

Question 5

Which of the following statements about free energy ($$\Delta G) is $$correct?

Accepted Answer

A reaction with $$\Delta G \u003c 0 is $$exergonic and will proceed spontaneously.

Question 6

Consider the hydrolysis of ATP: $$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + \mathrm{P_i}. $$Which of the following best describes the free energy change and spontaneity of this reaction?

Accepted Answer

The reaction has $$\Delta G \u003c 0$$ and is spontaneous.

Question 7

Which of the following best explains how ATP is able to drive energetically unfavorable reactions in the cell?

Accepted Answer

ATP hydrolysis provides free energy that can be coupled to drive endergonic reactions, making the overall $$\Delta G$$ negative.

Question 8

Which of the following statements about the structure and function of ATP is correct?

Accepted Answer

ATP stores energy in the bonds between its phosphate groups, which can be released during hydrolysis.

Question 9

How does an enzyme affect the activation energy ($$E_a) $$and the free energy change ($$\Delta G) of a $$chemical reaction?

Accepted Answer

It decreases $$E_a$$ but does not change $$\Delta G.$$

Question 10

A scientist is studying a reaction that occurs very slowly in the absence of an enzyme. When the enzyme is added, the reaction rate increases dramatically. Which of the following best explains this observation?

Accepted Answer

The enzyme lowers the activation energy required for the reaction to proceed.

Question 11

Which of the following best describes how enzymes achieve substrate specificity?

Accepted Answer

Enzymes have active sites with specific shapes and chemical properties that bind only to particular substrates.

Question 12

A patient is given a drug that acts as a competitive inhibitor of a key metabolic enzyme. What is the most likely effect of this drug on the enzyme's activity?

Accepted Answer

The drug binds to the enzyme's active site, preventing the substrate from binding and decreasing the reaction rate.

Question 13

During glycolysis, glucose is broken down into pyruvate, releasing energy. Which type of metabolic pathway does this represent, and what is the primary energy transformation?

Accepted Answer

Catabolic pathway; chemical energy in glucose to chemical energy in ATP

Question 14

If a reaction has a positive $$\Delta G$$ and is endergonic, which of the following is true?

Accepted Answer

The reaction requires an input of energy to proceed.

Question 15

A cell needs to synthesize a large, complex molecule from smaller precursors. Which of the following statements best describes the energy requirements and pathway involved?

Accepted Answer

This is an anabolic pathway that requires an input of energy, often supplied by ATP hydrolysis.

Question 16

Which of the following scenarios best illustrates the first law of thermodynamics in a biological system?

Accepted Answer

A plant converts sunlight into chemical energy during photosynthesis, with some energy lost as heat.

Question 17

Which of the following best describes the relationship between the transition state energy and the rate of a chemical reaction?

Accepted Answer

A lower transition state energy increases the reaction rate.

Question 18

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 an enzyme involved early in the pathway, preventing overproduction.

Question 19

Which of the following statements about enzyme reuse is correct?

Accepted Answer

Enzymes are not consumed in the reaction and can be used repeatedly for the same reaction.

Chapter 6 Study Guide: Metabolism, Energy, ATP, and Enzymes

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