Question 1

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

Accepted Answer

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

Question 2

According to the first law of thermodynamics, which of the following statements is correct?

Accepted Answer

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

Question 3

A bear eats a fish and then runs, releasing heat and waste products. Which law of thermodynamics does this scenario best illustrate?

Accepted Answer

The second law, because energy transformations increase the entropy of the universe.

Question 4

Which equation correctly relates the change in free energy ($$\Delta G) to $$enthalpy ($$\Delta H$$), entropy ($$\Delta S$$), and temperature ($$T$$)?

Accepted Answer

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

Question 5

Which of the following statements about exergonic and endergonic reactions is TRUE?

Accepted Answer

Exergonic reactions have $$\Delta G \u003c 0$$ and are spontaneous.

Question 6

Why are cells considered open systems in terms of thermodynamics?

Accepted Answer

They can exchange both energy and matter with their surroundings.

Question 7

Which of the following best explains why ATP is considered the 'energy currency' of the cell?

Accepted Answer

ATP releases energy when its terminal phosphate bond is broken, which can be used to drive endergonic reactions.

Question 8

A reaction has $$\Delta G = +3.4$$ kcal/mol. If it is coupled with ATP hydrolysis ($$\Delta G = -7.3$$ kcal/mol), what is the net $$\Delta G$$ for the coupled reaction?

Accepted Answer

$$-3.9$$ kcal/mol

Question 9

Which of the following is NOT a way that enzymes lower the activation energy ($$E_A) of a $$reaction?

Accepted Answer

Increasing the $$\Delta G of $$the reaction

Question 10

Which of the following statements about enzyme specificity is correct?

Accepted Answer

Each enzyme catalyzes a specific reaction due to the unique shape of its active site.

Question 11

A competitive inhibitor decreases the rate of an enzyme-catalyzed reaction by:

Accepted Answer

Binding to the active site and preventing substrate binding.

Question 12

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

Accepted Answer

The end product of a pathway inhibits an enzyme involved earlier in the pathway.

Question 13

Which of the following is an example of allosteric regulation?

Accepted Answer

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

Question 14

Why does the evolution of more complex organisms not violate the second law of thermodynamics?

Accepted Answer

Because entropy can decrease in a system as long as the total entropy of the universe increases.

Question 15

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

Accepted Answer

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

Question 16

Which of the following would most likely increase the rate of an enzyme-catalyzed reaction that is already saturated with substrate?

Accepted Answer

Adding more enzyme

Question 17

Which of the following is an example of a coenzyme?

Accepted Answer

Vitamin B12

Question 18

Which of the following best explains why enzymes are not consumed during chemical reactions?

Accepted Answer

Enzymes emerge from reactions in their original form and can be reused.

Question 19

Which of the following is a real-life example of energy coupling in cells?

Accepted Answer

ATP hydrolysis drives the active transport of sodium and potassium ions across the plasma membrane.

Chapter 8: An Introduction to Metabolism – The Energy of Life

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