Question 1

Which of the following best describes the difference between potential and kinetic energy in biological systems?

Accepted Answer

Potential energy is stored energy associated with position, while kinetic energy is the energy of motion.

Question 2

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

Accepted Answer

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

Question 3

A cell couples the hydrolysis of ATP to drive an endergonic reaction. If the hydrolysis of ATP has $$\Delta G = -30\ \mathrm{kJ/mol}$$ and the endergonic reaction has $$\Delta G = +20\ \mathrm{kJ/mol}$$, what is the net $$\Delta G$$ for the coupled reaction?

Accepted Answer

$$\Delta G = -10\ \mathrm{kJ/mol}$$

Question 4

Which of the following statements about enzymes is TRUE?

Accepted Answer

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

Question 5

Which scenario best illustrates energy coupling in a cell?

Accepted Answer

The breakdown of glucose during cellular respiration releases energy that is used to synthesize ATP.

Question 6

A reaction has $$\Delta G \u003c 0. $$What does this indicate about the reaction?

Accepted Answer

The reaction is exergonic and will occur spontaneously.

Question 7

Which of the following is an example of catabolism?

Accepted Answer

Breakdown of starch into glucose monomers.

Question 8

What is the role of the phosphorylated intermediate in ATP-driven endergonic reactions?

Accepted Answer

It has greater free energy, making the overall reaction exergonic.

Question 9

Which of the following best describes competitive inhibition of an enzyme?

Accepted Answer

A molecule binds to the active site, preventing substrate binding.

Question 10

Which process is responsible for regenerating ATP in cells?

Accepted Answer

Phosphorylation of ADP using energy released from catabolic reactions.

Question 11

Which of the following statements about the second law of thermodynamics is correct?

Accepted Answer

Every energy transfer increases the entropy of the universe.

Question 12

Which of the following is NOT a function of enzymes?

Accepted Answer

Changing the overall free energy ($$\Delta G) of a $$reaction.

Question 13

A metabolic pathway is self-regulating if:

Accepted Answer

The final product inhibits an enzyme earlier in the pathway.

Question 14

Which of the following best explains why spontaneous reactions may occur slowly in cells?

Accepted Answer

The activation energy ($$E_a) $$barrier is high, even if $$\Delta G is $$negative.

Question 15

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

Accepted Answer

Synthesis of starch from glucose monomers.

Question 16

Which statement about the induced fit model of enzyme activity is correct?

Accepted Answer

The substrate causes the enzyme to change shape, improving the fit and catalysis.

Question 17

If a reaction is at equilibrium, what is the value of $$\Delta G$$ and what does this mean for cellular work?

Accepted Answer

$$\Delta G = 0$$; no work can be done.

Question 18

Which of the following is a correct description of allosteric (non-competitive) inhibition?

Accepted Answer

An inhibitor binds to a different site, changing the enzyme's shape and reducing activity.

Question 19

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

Accepted Answer

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

Question 20

Which of the following factors can affect the rate of an enzyme-catalyzed reaction?

Accepted Answer

Temperature and pH.

Introduction to Metabolism and Enzymes (Chapter 8) – General Biology Study Notes

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