Question 1

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

Accepted Answer

Catabolic pathways break down complex molecules into simpler ones, releasing energy, while anabolic pathways build complex molecules from simpler ones, consuming energy.

Question 2

Which of the following is an example of kinetic energy in a biological system?

Accepted Answer

The movement of ions across a membrane during nerve impulse transmission.

Question 3

According to the first law of thermodynamics, which statement is correct regarding energy transformations in living organisms?

Accepted Answer

Energy is transformed from one form to another, but the total energy in a closed system remains constant.

Question 4

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

Accepted Answer

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

Question 5

A reaction has $$\Delta G = -7.3$$ kcal/mol. Which of the following statements is true about this reaction?

Accepted Answer

The reaction is exergonic and spontaneous.

Question 6

Which of the following best explains how ATP hydrolysis powers cellular work?

Accepted Answer

ATP hydrolysis transfers a phosphate group to another molecule, increasing its free energy and making it more reactive.

Question 7

Which structural feature of ATP is most directly responsible for its ability to store and release energy?

Accepted Answer

The three phosphate groups linked by high-energy bonds.

Question 8

In a coupled reaction, the hydrolysis of ATP ($$\Delta G = -7.3$$ kcal/mol) is used to drive a reaction with $$\Delta G = +5.0$$ kcal/mol. What is the net $$\Delta G$$ for the coupled reaction?

Accepted Answer

$$\Delta G = -2.3$$ kcal/mol

Question 9

Which statement best describes the role of enzymes in metabolic reactions?

Accepted Answer

Enzymes lower the activation energy, allowing reactions to proceed more rapidly.

Question 10

Which of the following scenarios best illustrates enzyme specificity?

Accepted Answer

An enzyme binds only to a specific substrate due to the shape of its active site.

Question 11

How does increasing substrate concentration affect the rate of an enzyme-catalyzed reaction, assuming enzyme concentration is constant?

Accepted Answer

The reaction rate increases until the enzyme becomes saturated, then levels off.

Question 12

Which of the following best describes the effect of temperature on enzyme activity?

Accepted Answer

Enzyme activity increases with temperature up to an optimal point, then decreases due to denaturation.

Question 13

A patient is diagnosed with a genetic disorder that affects the structure of a key metabolic enzyme. Which of the following is the most likely consequence?

Accepted Answer

The enzyme may lose its substrate specificity, leading to metabolic imbalances.

Question 14

Which of the following statements about activation energy is correct?

Accepted Answer

Activation energy is the energy required to initiate a chemical reaction.

Question 15

Which of the following is a real-world example of an exergonic reaction in human physiology?

Accepted Answer

Hydrolysis of ATP to ADP and inorganic phosphate.

Question 16

Which of the following best explains how cells maintain order despite the second law of thermodynamics?

Accepted Answer

Cells use energy from catabolic reactions to build and maintain complex structures, increasing order locally while increasing entropy in the surroundings.

Question 17

Which of the following is true regarding enzyme regulation in metabolic pathways?

Accepted Answer

Enzyme activity can be regulated by inhibitors, activators, and changes in environmental conditions.

Question 18

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

Accepted Answer

The reaction is at equilibrium and no net change will occur.

Question 19

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

Accepted Answer

The enzyme changes shape slightly to better fit the substrate upon binding.

Question 20

Which of the following is a consequence of a non-spontaneous reaction in a cell?

Accepted Answer

The reaction requires coupling to an energetically favorable process, such as ATP hydrolysis, to occur.

Metabolism, Free Energy, ATP, and Enzymes: Study Notes for General Biology

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