Question 1

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

Accepted Answer

Anabolic pathways build complex molecules from simpler ones, requiring energy input, while catabolic pathways break down complex molecules into simpler ones, releasing energy.

Question 2

According to the first law of thermodynamics, which of the following is true about energy in biological systems?

Accepted Answer

Energy can be transferred and transformed, but cannot be created or destroyed.

Question 3

A cell uses ATP to drive the endergonic reaction of glucose phosphorylation. Which process best describes how ATP powers this reaction?

Accepted Answer

ATP hydrolysis transfers a phosphate group to glucose, making it more reactive.

Question 4

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

Accepted Answer

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

Question 5

Which of the following best explains why enzymes are necessary for metabolic reactions in living cells?

Accepted Answer

Enzymes lower the activation energy ($E_a$) required for reactions to proceed.

Question 6

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the enzyme's active site and blocking substrate access.

Question 7

Which of the following is a real-world example of the second law of thermodynamics in biological systems?

Accepted Answer

A termite digesting plant material and releasing heat to the environment.

Question 8

If a reaction has a negative $\Delta G$, which of the following statements is true?

Accepted Answer

The reaction is spontaneous and can perform work.

Question 9

Which of the following factors can affect the catalytic ability of an enzyme?

Accepted Answer

Temperature, pH, and the presence of cofactors.

Question 10

A cell is exposed to a noncompetitive inhibitor. What is the most likely effect on enzyme activity?

Accepted Answer

The inhibitor binds elsewhere on the enzyme, changing its shape and reducing activity.

Question 11

Which of the following best describes feedback inhibition in metabolic pathways?

Accepted Answer

The end product of a pathway inhibits an enzyme earlier in the pathway, preventing overproduction.

Question 12

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

Accepted Answer

ATP is regenerated by the addition of a phosphate group to ADP using energy from catabolic reactions.

Question 13

Which statement about enzyme-substrate specificity is correct?

Accepted Answer

Enzymes are specific to their substrates due to the shape of their active site.

Question 14

Which of the following is an example of allosteric regulation of an enzyme?

Accepted Answer

A regulatory molecule binds to a site other than the active site, altering enzyme activity.

Question 15

A scientist measures the free energy change ($\Delta G$) for a reaction and finds it to be $+15$ kJ/mol. What does this indicate about the reaction?

Accepted Answer

The reaction is endergonic and requires energy input to proceed.

Question 16

Which of the following best explains why heat is not a useful way to speed up reactions in living cells?

Accepted Answer

Heat can denature proteins and cannot be directed at specific reactions.

Question 17

Which of the following is true about the relationship between free energy and stability in a system?

Accepted Answer

Systems with lower free energy ($G$) are more stable.

Question 18

Which of the following is a function of ATP in cellular work?

Accepted Answer

ATP powers chemical, transport, and mechanical work in cells.

Question 19

Which of the following statements about metabolic equilibrium in living cells is correct?

Accepted Answer

Cells maintain open systems, preventing metabolic equilibrium and allowing continuous work.

Ch.8- An Introduction to Metabolism

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