Question 1

Which statement best describes the First Law of Thermodynamics as it applies to biological systems?

Accepted Answer

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

Question 2

A metabolic pathway that synthesizes proteins from amino acids is best classified as:

Accepted Answer

Anabolic

Question 3

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

Accepted Answer

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

Question 4

Which scenario would most likely result in a spontaneous reaction according to the Second Law of Thermodynamics?

Accepted Answer

A reaction with a negative $$\Delta G$$ and increasing entropy.

Question 5

ATP is often described as the 'energy currency' of the cell because:

Accepted Answer

It can be regenerated by adding a phosphate group to ADP.

Question 6

Which of the following best explains how enzymes speed up chemical reactions?

Accepted Answer

By lowering the activation energy required for the reaction.

Question 7

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the active site and competing with the substrate.

Question 8

Which of the following is true about entropy ($$S) in $$biological systems?

Accepted Answer

Entropy of the universe always increases for spontaneous reactions.

Question 9

In feedback inhibition, the end product of a metabolic pathway:

Accepted Answer

Binds to an allosteric site to decrease pathway activity.

Question 10

Which of the following statements about cofactors is correct?

Accepted Answer

Cofactors can be either inorganic (such as metal ions) or organic.

Question 11

A cell is observed to have enzymes for cellular respiration only in its mitochondria. This is an example of:

Accepted Answer

Enzyme localization

Question 12

Which of the following best describes allosteric regulation of enzymes?

Accepted Answer

A regulatory molecule binds to a site other than the active site, affecting enzyme function.

Question 13

Which of the following is a correct statement about the role of ATP in energy coupling?

Accepted Answer

ATP hydrolysis is used to drive endergonic reactions by transferring a phosphate group.

Question 14

A reaction has $$\Delta H = +10 kJ/$$mol and $$\Delta S = +0.05 kJ/($$mol\cdot K). At $$T = 300 K$$, what is $$\Delta G$$ for the reaction?

Accepted Answer

$$\Delta G = +10 - (300 	imes 0.05) = -5 kJ/$$mol

Question 15

Which of the following would most likely increase the specificity of an enzyme for its substrate?

Accepted Answer

Altering amino acids in the active site to better fit the substrate.

Question 16

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

Accepted Answer

Synthesis of proteins from amino acids

Question 17

A noncompetitive inhibitor affects enzyme activity by:

Accepted Answer

Binding away from the active site and decreasing enzyme activity.

Question 18

Which of the following best describes the concept of energy coupling in cells?

Accepted Answer

Using an exergonic process to drive an endergonic one.

Question 19

Which of the following statements about spontaneous reactions is correct?

Accepted Answer

Spontaneous reactions have a negative $$\Delta G$$ and can occur without energy input.

Question 20

Cooperativity in enzyme regulation refers to:

Accepted Answer

A substrate molecule priming an enzyme to bind additional substrates more easily.

Metabolism, Thermodynamics, and Enzyme Function in Biology

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