Question 1

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

Accepted Answer

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

Question 2

Which equation correctly represents the relationship between free energy, enthalpy, entropy, and temperature?

Accepted Answer

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

Question 3

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

Accepted Answer

The reaction is spontaneous and can perform work.

Question 4

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

Accepted Answer

The hydrolysis of ATP to ADP and $$P_i$$ powers the active transport of ions across a membrane.

Question 5

Why is ATP considered a high-energy molecule?

Accepted Answer

Because the repulsion between the negatively charged phosphate groups creates high potential energy.

Question 6

Which statement about enzymes is correct?

Accepted Answer

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

Question 7

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

Accepted Answer

Competing with the substrate for binding at the active site.

Question 8

Which of the following best explains why cells never reach metabolic equilibrium?

Accepted Answer

Cells constantly allow materials to flow in and out, preventing equilibrium and enabling continuous work.

Question 9

Which of the following is true about the effect of temperature on enzyme activity?

Accepted Answer

Each enzyme has an optimal temperature, above which the enzyme denatures and activity decreases.

Question 10

Which of the following is an example of feedback inhibition?

Accepted Answer

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

Question 11

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

Accepted Answer

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

Question 12

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 properly.

Question 13

A reaction in a cell has $$\Delta G = 0. $$What does this imply about the cell?

Accepted Answer

The cell is dead, as metabolic equilibrium has been reached.

Question 14

Which of the following is NOT a way that enzymes lower activation energy ($$E_A$$)?

Accepted Answer

Changing the $$\Delta G of $$the reaction.

Question 15

Which of the following is an example of an exergonic reaction?

Accepted Answer

The hydrolysis of ATP to ADP and $$P_i.$$

Question 16

Which of the following statements about allosteric regulation is correct?

Accepted Answer

Allosteric regulation involves binding of a regulatory molecule to a site other than the active site, which can either inhibit or stimulate enzyme activity.

Question 17

Which of the following best explains why the hydrolysis of sucrose is extremely slow at room temperature without an enzyme?

Accepted Answer

The activation energy barrier is too high for the reaction to proceed rapidly.

Question 18

Which of the following is a real-life example of irreversible enzyme inhibition?

Accepted Answer

Sarin gas binding covalently to acetylcholinesterase.

Question 19

Which of the following statements about the ATP cycle is correct?

Accepted Answer

ATP is regenerated from ADP and $$P_i$$ using energy from exergonic reactions.

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

Guida di studio - Domande di pratica

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