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 bear eats a fish and then runs, converting chemical energy in food to kinetic energy and heat. Which law of thermodynamics does this scenario best illustrate?

Accepted Answer

The first law of thermodynamics: energy can be transferred and transformed, but not created or destroyed.

Question 3

Which of the following statements about the second law of thermodynamics is correct?

Accepted Answer

Every energy transfer or transformation increases the entropy (disorder) of the universe.

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

A reaction has $$\Delta G \u003c 0. $$What can you conclude about this reaction?

Accepted Answer

It is exergonic and spontaneous.

Question 6

Which of the following best explains why ATP is able to power cellular work?

Accepted Answer

ATP hydrolysis releases energy due to the repulsion between its phosphate groups, and this energy is used to drive endergonic reactions.

Question 7

Which of the following is NOT a correct statement about enzymes?

Accepted Answer

Enzymes change the $$\Delta G of a $$reaction.

Question 8

A scientist increases the substrate concentration in an enzyme-catalyzed reaction, but the reaction rate no longer increases. What is the most likely explanation?

Accepted Answer

The enzyme is saturated; all active sites are occupied.

Question 9

Which of the following best describes the induced-fit model of enzyme function?

Accepted Answer

The enzyme changes its shape slightly to fit more snugly around the substrate after binding.

Question 10

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

Accepted Answer

The end product of a pathway binds to an enzyme early in the pathway, decreasing its activity.

Question 11

Which of the following is an example of an allosteric regulator?

Accepted Answer

A molecule that binds to a site other than the active site, changing the enzyme's shape and activity.

Question 12

Which of the following best explains why increasing temperature beyond an enzyme's optimal range decreases its activity?

Accepted Answer

The enzyme denatures, losing its three-dimensional structure and active site.

Question 13

A competitive inhibitor decreases the rate of an enzyme-catalyzed reaction by:

Accepted Answer

Binding to the active site and blocking substrate entry.

Question 14

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

Accepted Answer

ATP is regenerated from ADP and inorganic phosphate using energy from catabolic (exergonic) reactions.

Question 15

Which of the following best describes the role of cofactors in enzyme activity?

Accepted Answer

Cofactors are nonprotein helpers that are required for some enzymes to function.

Question 16

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

Accepted Answer

The reaction is endergonic and requires an input of energy.

Question 17

Which of the following is a real-life example of an anabolic pathway?

Accepted Answer

The synthesis of proteins from amino acids.

Question 18

Which of the following statements about equilibrium in metabolic reactions is correct?

Accepted Answer

A cell at metabolic equilibrium is dead.

Question 19

Which of the following best explains why the hydrolysis of ATP is highly exergonic?

Accepted Answer

The repulsion between the negatively charged phosphate groups is relieved when ATP is hydrolyzed.

Question 20

A patient is given a drug that acts as a noncompetitive inhibitor of a key metabolic enzyme. What is the most likely effect of this drug?

Accepted Answer

The drug will bind to a site other than the active site, changing the enzyme's shape and reducing its activity.

Chapter 8: An Introduction to Metabolism – Study Notes for General Biology

Guida di studio - Domande di pratica

Study guide - Flashcard