Question 1

Which of the following best describes a metabolic pathway as shown in the first image (A → B → C → D)?

Accepted Answer

A sequence of reactions where the product of one reaction serves as the substrate for the next, each catalyzed by a different enzyme.

Question 2

The spiral pattern seen in the second image (sea urchin and plant) is an example of biological order. According to the second law of thermodynamics, how is this order maintained in living organisms?

Accepted Answer

By using energy to maintain order locally, while increasing the entropy of the surroundings.

Question 3

Refer to the third image (bar graphs of energy changes). Which of the following statements is correct regarding exergonic and endergonic reactions?

Accepted Answer

Exergonic reactions have $$\Delta G  0$$ and require energy input.

Question 4

The molecule shown in the fourth image is ATP. Which part of the molecule is responsible for storing and releasing energy?

Accepted Answer

The chain of three phosphate groups

Question 5

Based on the ATP cycle shown in the fifth image, which statement best explains how ATP couples exergonic and endergonic reactions?

Accepted Answer

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

Question 6

In the sixth image (reaction progress diagram), what does the difference between the peak of the curve and the reactants represent?

Accepted Answer

The activation energy ($$E_A) $$required for the reaction to proceed

Question 7

Which of the following best describes the effect of an enzyme on a chemical reaction, as shown in the tenth image (reaction progress with and without enzyme)?

Accepted Answer

Enzymes lower the activation energy ($$E_A) $$but do not change the overall free energy change ($$\Delta G) of $$the reaction.

Question 8

The eleventh image shows the enzyme-substrate cycle. What is the role of the active site in enzyme function?

Accepted Answer

It is a specific region where substrates bind and the reaction is catalyzed.

Question 9

The thirteenth image shows a vitamin structure. What is the role of vitamins such as B12 in enzyme activity?

Accepted Answer

They act as organic coenzymes, assisting enzymes in catalysis.

Question 10

According to the fourteenth image (enzyme velocity vs. substrate concentration), what happens when an enzyme becomes saturated with substrate?

Accepted Answer

The reaction rate levels off and reaches a maximum velocity ($$V_{max}).$$

Question 11

The fifteenth image shows enzyme inhibition. Which of the following statements is true about competitive and noncompetitive inhibitors?

Accepted Answer

Competitive inhibitors bind to the active site, while noncompetitive inhibitors bind to a different site on the enzyme.

Question 12

The sixteenth image shows allosteric regulation. What is the effect of an allosteric inhibitor on an enzyme?

Accepted Answer

It binds to a regulatory site, stabilizing the inactive form of the enzyme.

Question 13

The seventeenth image shows cooperativity. Which of the following best describes this phenomenon?

Accepted Answer

The binding of one substrate molecule increases the enzyme's activity at other active sites.

Question 14

The eighteenth image shows feedback inhibition. What is the main advantage of this regulatory mechanism in metabolic pathways?

Accepted Answer

It prevents the accumulation of the end product and conserves cellular resources.

Question 15

The nineteenth image shows mitochondria. Why is the compartmentalization of enzymes within organelles such as mitochondria important for metabolism?

Accepted Answer

It restricts enzymatic reactions to specific locations, increasing efficiency and regulation.

Question 16

Which of the following equations correctly represents the change in free energy for a chemical reaction?

Accepted Answer

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

Question 17

If a reaction has $$\Delta G = 0$$, what can be concluded about the reactants and products?

Accepted Answer

The reaction is at equilibrium and no net change occurs.

Question 18

Which of the following best explains why even spontaneous reactions may not occur rapidly in the absence of enzymes?

Accepted Answer

The activation energy barrier is too high.

Question 19

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

Accepted Answer

The synthesis of proteins from amino acids.

Question 20

High levels of ATP in a cell are most likely to have what effect on catabolic enzymes?

Accepted Answer

Inhibit catabolic enzymes to prevent excess ATP production.

Energy, Enzymes, and Metabolism: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard