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; anabolic pathways build complex molecules from simpler ones, requiring energy input.

Question 2

Which of the following is an example of a catabolic reaction?

Accepted Answer

Breakdown of glucose during cellular respiration.

Question 3

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

Accepted Answer

Energy cannot be created or destroyed, only transferred or transformed.

Question 4

Which equation correctly represents the change in Gibbs free energy ($$\Delta G) $$for a chemical reaction?

Accepted Answer

$$\Delta G = G_{products} - G_{reactants}$$

Question 5

Why do anabolic reactions require an input of energy?

Accepted Answer

Because they build complex molecules from simpler ones, which is an endergonic process.

Question 6

Which of the following best describes the role of enzymes in biological reactions?

Accepted Answer

Enzymes lower the activation energy, speeding up the reaction without being consumed.

Question 7

Which model best explains how substrates bind to enzymes?

Accepted Answer

Induced fit model, where the enzyme's active site molds around the substrate, stabilizing the transition state.

Question 8

Which factor does NOT typically affect enzyme activity?

Accepted Answer

Color of the enzyme

Question 9

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the active site and blocking substrate binding.

Question 10

Which statement about feedback inhibition is correct?

Accepted Answer

It occurs when the end product of a metabolic pathway inhibits an enzyme involved earlier in the pathway.

Question 11

Which of the following is an example of potential energy in biological systems?

Accepted Answer

Chemical bonds in glucose molecules.

Question 12

Which of the following is true regarding the second law of thermodynamics in biological systems?

Accepted Answer

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

Question 13

Which of the following reactions is exergonic?

Accepted Answer

Cellular respiration: $$C_6H_{12}O_6$ + 6 O_2$ \rightarrow 6 CO_2$ + 6 H_2O$$

Question 14

Which statement about enzyme specificity is correct?

Accepted Answer

Each enzyme typically catalyzes only one or a few specific reactions.

Question 15

How does temperature generally affect enzyme activity?

Accepted Answer

Enzyme activity increases with temperature up to an optimal point, then decreases as the enzyme denatures.

Question 16

Which of the following is a function of cofactors in enzyme activity?

Accepted Answer

They are required for some enzymes to function properly.

Question 17

Which of the following best describes allosteric regulation of enzymes?

Accepted Answer

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

Question 18

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

Accepted Answer

Penicillin acting as a competitive inhibitor against transpeptidase in bacteria.

Question 19

A student mixes an enzyme with its substrate and measures the reaction rate at different pH values. At pH 2, the rate is high; at pH 8, the rate is low. Which enzyme is most likely being studied?

Accepted Answer

Pepsin (stomach enzyme)

Question 20

Which of the following statements about the effect of noncompetitive inhibitors on enzymes is correct?

Accepted Answer

They bind to a different site, changing the enzyme's shape and reducing its activity.

Metabolism, Bioenergetics, and Enzymes: Study Notes for General Biology

Guida di studio - Domande di pratica

Study guide - Flashcard