Question 1

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

Accepted Answer

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

Question 2

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

Accepted Answer

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

Question 3

A cell maintains a highly ordered structure. How does this not violate the second law of thermodynamics?

Accepted Answer

Cells decrease their own entropy but increase the entropy of their surroundings, resulting in a net increase in universal entropy.

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 is true about exergonic reactions?

Accepted Answer

They occur spontaneously and have a negative $$\Delta G.$$

Question 6

How does ATP typically power cellular work?

Accepted Answer

By coupling the exergonic hydrolysis of ATP to endergonic reactions, often through phosphorylation of reactants.

Question 7

Which of the following best describes the ATP cycle in cells?

Accepted Answer

ATP is synthesized from ADP and $$P_i$$ using energy from catabolic pathways, and hydrolyzed to ADP and $$P_i to $$power cellular work.

Question 8

Refer to the enzyme-catalyzed reaction graph (second image). What does the lower peak of the red curve represent?

Accepted Answer

The activation energy ($$E_A) of $$the reaction with an enzyme.

Question 9

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

Accepted Answer

Increasing the free energy change ($$\Delta G) of $$the reaction.

Question 10

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

Accepted Answer

Binding to the active site, preventing substrate binding.

Question 11

Which of the following best describes allosteric regulation of enzymes?

Accepted Answer

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

Question 12

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

Accepted Answer

Allosterically inhibits an enzyme involved earlier in the pathway.

Question 13

Which of the following scenarios is an example of energy coupling in a cell?

Accepted Answer

The hydrolysis of ATP is used to drive the synthesis of glutamine from glutamate and ammonia.

Question 14

Which of the following statements about enzymes is correct?

Accepted Answer

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

Question 15

A scientist discovers a new enzyme that works best at pH 2 and 37°C. Where in the human body is this enzyme most likely to be found?

Accepted Answer

In the stomach.

Question 16

Which of the following is a real-life example of feedback inhibition?

Accepted Answer

The end product of the pathway that synthesizes isoleucine from threonine inhibits the first enzyme in the pathway.

Question 17

Which of the following best explains why enzymes are highly specific for their substrates?

Accepted Answer

The active site of an enzyme has a unique shape that fits only specific substrate molecules.

Question 18

Which of the following would most likely result if a cell's enzymes were all denatured by high temperature?

Accepted Answer

Metabolic reactions would slow down or stop, threatening cell survival.

Question 19

Which of the following is a consequence of the second law of thermodynamics for living organisms?

Accepted Answer

Living organisms can decrease entropy in their surroundings as they maintain order internally.

Question 20

Which of the following is NOT a function of ATP in the cell?

Accepted Answer

Acting as a building block for DNA synthesis.

Chapter 8: An Introduction to Metabolism – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards