Question 1

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

Accepted Answer

Catabolic pathways break down complex molecules into simpler ones, releasing energy, while anabolic pathways build complex molecules from simpler ones, consuming energy.

Question 2

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

Accepted Answer

Energy cannot be created or destroyed, only transformed from one form to another.

Question 3

In the context of the second law of thermodynamics, what happens to the entropy of the universe when a living organism becomes more ordered?

Accepted Answer

The entropy of the universe increases.

Question 4

Which equation correctly relates free energy ($$G$$), total energy ($$H$$), entropy ($$S$$), and temperature ($$T) in a $$system?

Accepted Answer

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

Question 5

Refer to the first image (A and B). Which type of reaction is represented by diagram A, and what is the sign of $$\Delta G$$ for this reaction?

Accepted Answer

Exergonic; $$\Delta G \u003c 0$$

Question 6

Which of the following statements about ATP is correct?

Accepted Answer

ATP releases energy when its terminal phosphate group is removed, forming ADP and inorganic phosphate.

Question 7

How do enzymes speed up chemical reactions in biological systems?

Accepted Answer

By lowering the activation energy ($$E_A) $$required for the reaction to proceed.

Question 8

Refer to the second image. What is the effect of the enzyme on the activation energy of the reaction?

Accepted Answer

The enzyme decreases the activation energy required for the reaction.

Question 9

Which of the following best describes the role of competitive inhibitors in enzyme activity?

Accepted Answer

They bind to the enzyme's active site, blocking substrate binding.

Question 10

A scientist observes that the addition of a certain molecule to an enzyme-catalyzed reaction decreases the reaction rate, but this effect can be overcome by increasing the substrate concentration. What type of molecule is most likely responsible for this effect?

Accepted Answer

A competitive inhibitor

Question 11

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 12

Which of the following is NOT a way that enzymes lower the activation energy of a reaction?

Accepted Answer

Increasing the temperature of the cell

Question 13

Which of the following statements about the localization of enzymes within a cell is correct?

Accepted Answer

Some enzymes are grouped into complexes, incorporated into membranes, or contained inside organelles to help order metabolism.

Question 14

Which of the following best explains why the hydrolysis of ATP is often coupled to endergonic reactions in cells?

Accepted Answer

The hydrolysis of ATP is exergonic and provides energy to drive endergonic reactions.

Question 15

A reaction has $$\Delta G = +15 kJ/$$mol. Which of the following statements is true about this reaction?

Accepted Answer

The reaction is endergonic and requires an input of energy.

Question 16

Which of the following is an example of an emergent property in the context of metabolism?

Accepted Answer

The organization of metabolic pathways resulting in new properties not present in individual enzymes.

Question 17

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

Accepted Answer

The enzyme changes shape slightly to fit the substrate more closely when the substrate binds.

Question 18

Which of the following is a correct statement about the relationship between exergonic and endergonic reactions in cellular metabolism?

Accepted Answer

Exergonic reactions release energy that can be used to drive endergonic reactions through energy coupling.

Introduction to Metabolism: Energy, Enzymes, and Regulation

Guida di studio - Domande di pratica

Study guide - Flashcard