Question 1

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

Accepted Answer

Anabolic pathways consume energy to synthesize complex molecules, while catabolic pathways release energy by breaking down complex molecules.

Question 2

According to the first law of thermodynamics, which of the following statements is correct?

Accepted Answer

Energy can be transferred and transformed, but it cannot be created or destroyed.

Question 3

A reaction has a $$\Delta G = -5$$ kcal/mol. Which of the following is true about this reaction?

Accepted Answer

The reaction is spontaneous and releases free energy.

Question 4

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 more rapidly.

Question 5

Which of the following scenarios is an example of energy coupling in cells?

Accepted Answer

The hydrolysis of ATP is used to drive the synthesis of glucose from CO$$_2$$ and H$$_2O.$$

Question 6

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

Accepted Answer

ATP regeneration from ADP and Pi is an endergonic process that requires energy input.

Question 7

A scientist observes that increasing the substrate concentration in an enzymatic reaction increases the reaction rate, but only up to a certain point. What is the best explanation for this observation?

Accepted Answer

The enzyme is saturated, and all active sites are occupied, so adding more substrate does not increase the rate.

Question 8

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

Accepted Answer

It competes with the substrate for binding to the active site and can be overcome by increasing substrate concentration.

Question 9

Which of the following is an example of 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 10

Which of the following statements about entropy is correct?

Accepted Answer

Every energy transfer or transformation increases the entropy of the universe.

Question 11

A cell that has reached metabolic equilibrium is considered dead. Why?

Accepted Answer

At equilibrium, the cell can no longer perform work because $$\Delta G = 0$$ and no energy is available for cellular processes.

Question 12

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

Accepted Answer

Cofactors are non-protein components required for the proper functioning of some enzymes.

Question 13

Which of the following equations correctly represents the relationship between free energy, enthalpy, entropy, and temperature?

Accepted Answer

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

Question 14

Which of the following is NOT a form of kinetic energy?

Accepted Answer

Chemical energy

Question 15

Which of the following best explains why many spontaneous reactions do not occur instantly?

Accepted Answer

The activation energy barrier must be overcome for the reaction to proceed.

Question 16

Which of the following is an example of an open system in biological terms?

Accepted Answer

A living cell that exchanges both energy and matter with its environment.

Question 17

Which of the following statements about enzyme specificity is correct?

Accepted Answer

Enzyme specificity is due to a complementary fit between the enzyme's active site and the substrate.

Question 18

Which of the following is a real-life example of the second law of thermodynamics?

Accepted Answer

A bear converting chemical energy from food into kinetic energy and heat while running.

Question 19

Which of the following best describes allosteric regulation of enzymes?

Accepted Answer

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

Chapter 8: An Introduction to Metabolism and Enzyme Function

Guida di studio - Domande di pratica

Study guide - Flashcard