Question 1

Which statement best describes the relationship between catabolic and anabolic pathways in cellular metabolism?

Accepted Answer

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

Question 2

A bear eats a fish and uses the energy to run. Which law of thermodynamics is illustrated when the bear releases heat during this process?

Accepted Answer

The second law of thermodynamics, because energy transfer increases entropy and releases heat.

Question 3

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

Accepted Answer

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

Question 4

Which of the following is true for a spontaneous reaction in a biological system?

Accepted Answer

$$\Delta G is $$negative and the system becomes more stable.

Question 5

In the hydrolysis of ATP, which statement is correct regarding the energy released?

Accepted Answer

The energy comes from the chemical change to a state of lower free energy in the products.

Question 6

Which of the following best describes how ATP powers cellular work?

Accepted Answer

ATP hydrolysis releases energy that is used to drive endergonic reactions by phosphorylation.

Question 7

Which of the following is NOT a mechanism by which enzymes lower activation energy?

Accepted Answer

Increasing the free energy ($$\Delta G) of $$the reaction.

Question 8

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the active site and blocking substrate access.

Question 9

Which environmental factor is most likely to cause an enzyme to denature?

Accepted Answer

A significant increase in temperature above the enzyme's optimum.

Question 10

Feedback inhibition in a metabolic pathway serves to:

Accepted Answer

Prevent the cell from wasting chemical resources by shutting down the pathway when enough product is made.

Question 11

Which of the following best explains why an organism is considered an open system?

Accepted Answer

It exchanges both energy and matter with its surroundings.

Question 12

Which of the following is a real-life example of an exergonic reaction?

Accepted Answer

Cellular respiration in animals.

Question 13

Which statement about enzyme specificity is correct?

Accepted Answer

Enzyme specificity is determined by the shape of the active site and its complementary fit with the substrate.

Question 14

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

Accepted Answer

The enzyme changes shape slightly to fit the substrate, enhancing catalysis.

Question 15

Which of the following is true about the effect of substrate concentration on the rate of an enzyme-catalyzed reaction?

Accepted Answer

Increasing substrate concentration increases the reaction rate until the enzyme is saturated.

Question 16

Which of the following is an example of allosteric regulation?

Accepted Answer

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

Question 17

Which statement 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 18

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

Accepted Answer

ATP is regenerated from ADP and inorganic phosphate using energy from catabolic reactions.

Question 19

Which of the following best illustrates cooperativity in enzyme function?

Accepted Answer

The binding of oxygen to hemoglobin increases the affinity for additional oxygen molecules.

Question 20

Which of the following is a correct statement about equilibrium in metabolic reactions?

Accepted Answer

A system at equilibrium has maximum stability and cannot perform work.

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

Guida di studio - Domande di pratica