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 hydroelectric dam stores water at a high altitude. Which type of energy does the water possess before it is released to generate electricity?

Accepted Answer

Potential energy

Question 3

Which law of thermodynamics explains why energy cannot be created or destroyed, only transformed or transferred?

Accepted Answer

First law of thermodynamics

Question 4

According to the second law of thermodynamics, what happens to the entropy of the universe during every energy transfer or transformation?

Accepted Answer

Entropy increases

Question 5

Which equation correctly relates the change in free energy ($$\Delta G) to $$enthalpy ($$\Delta H$$), entropy ($$\Delta S$$), and temperature ($$T$$)?

Accepted Answer

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

Question 6

A reaction has $$\Delta G \u003c 0. $$What does this indicate about the reaction?

Accepted Answer

The reaction is spontaneous and can perform work.

Question 7

Why do metabolic reactions in living cells never reach equilibrium?

Accepted Answer

Continuous flow of materials in and out of the cell prevents equilibrium.

Question 8

Which of the following statements about ATP is correct?

Accepted Answer

ATP hydrolysis releases energy that can be used to drive endergonic reactions.

Question 9

What is the role of phosphorylation in cellular work?

Accepted Answer

It transfers a phosphate group to a molecule, making it more reactive and able to perform work.

Question 10

Which of the following best explains why enzymes are necessary for many biological reactions?

Accepted Answer

Enzymes lower the activation energy barrier, allowing reactions to occur at moderate temperatures.

Question 11

A patient is exposed to sarin gas, which covalently binds to acetylcholinesterase. What type of enzyme inhibition is this?

Accepted Answer

Irreversible inhibition

Question 12

Which of the following would most likely increase the rate of an enzyme-catalyzed reaction that is currently saturated with substrate?

Accepted Answer

Add more enzyme to the reaction mixture.

Question 13

Pepsin is a digestive enzyme in the human stomach. At which pH does pepsin function most effectively?

Accepted Answer

pH 2

Question 14

Which of the following is true about competitive enzyme inhibitors?

Accepted Answer

They bind to the active site and can be overcome by increasing substrate concentration.

Question 15

Which process is an example of feedback inhibition in metabolic pathways?

Accepted Answer

The end product of a pathway binds to an enzyme early in the pathway, shutting down further production.

Question 16

A mutation changes the amino acid sequence at the active site of an enzyme. What is the most likely consequence?

Accepted Answer

The enzyme may lose its substrate specificity or gain a new function.

Question 17

Which of the following is an example of allosteric regulation?

Accepted Answer

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

Question 18

Which statement best describes the relationship between exergonic and endergonic reactions in cells?

Accepted Answer

Cells couple exergonic reactions to drive endergonic reactions using ATP.

Question 19

Which of the following best explains why heat is not a useful way to speed up reactions in living cells?

Accepted Answer

Heat can denature proteins and speed up all reactions indiscriminately.

Chapter 8: An Introduction to Metabolism (Campbell Biology)

Guida di studio - Domande di pratica

Study guide - Flashcard