Question 1

Which of the following best describes the difference between catabolic and anabolic pathways in cellular 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 second law of thermodynamics, which of the following statements is correct regarding energy transformations in living organisms?

Accepted Answer

Energy transformations increase the entropy (disorder) of the universe.

Question 3

A chemical reaction has a $$\Delta G ($$change in free energy) of $$-7.3$$ kcal/mol. Which of the following statements is true about this reaction?

Accepted Answer

The reaction is exergonic and spontaneous.

Question 4

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 hydrolyzed: $$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} ightarrow \mathrm{ADP} + \mathrm{P}_i + 	ext{energy}$$

Question 5

Which of the following scenarios best illustrates the first law of thermodynamics in a biological context?

Accepted Answer

A cheetah converts the chemical energy from food into kinetic energy for running.

Question 6

Which of the following is a correct statement about enzyme function?

Accepted Answer

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

Question 7

A scientist adds a competitive inhibitor to an enzyme-catalyzed reaction. What is the most likely effect?

Accepted Answer

The inhibitor binds to the enzyme's active site, preventing substrate binding.

Question 8

Which of the following best describes the role of cofactors in enzyme activity?

Accepted Answer

Cofactors are non-protein helpers, such as metal ions (e.g., iron, zinc) or organic molecules (e.g., NAD$$^+$$, FAD), required for enzyme function.

Question 9

Which of the following reactions is most likely to be coupled with ATP hydrolysis in a cell?

Accepted Answer

A reaction with $$\Delta G = +5$$ kcal/mol

Question 10

A patient is diagnosed with a genetic disorder that results in a nonfunctional enzyme in a metabolic pathway. Which of the following is the most likely consequence?

Accepted Answer

The substrate for the defective enzyme will accumulate, and the product will be deficient.

Question 11

Which of the following best describes an exergonic reaction?

Accepted Answer

A reaction that releases energy and has a negative $$\Delta G$$ value.

Question 12

Which of the following environmental factors can affect enzyme activity in cells?

Accepted Answer

Both temperature and pH, as well as the presence of cofactors

Question 13

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

Accepted Answer

The synthesis of proteins from amino acids

Question 14

If a reaction is non-spontaneous, which of the following must be true?

Accepted Answer

The reaction requires an input of energy to proceed.

Question 15

Which of the following best explains why heat is released during muscle contraction?

Accepted Answer

Heat is a byproduct of the conversion of chemical energy to mechanical energy, consistent with the second law of thermodynamics.

Question 16

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

Accepted Answer

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

Question 17

Which of the following best describes the relationship between entropy and biological order?

Accepted Answer

Living organisms decrease their own entropy while increasing the entropy of their surroundings.

Question 18

Which of the following is a real-life example of an enzyme-catalyzed reaction?

Accepted Answer

The breakdown of sucrose into glucose and fructose by sucrase

Question 19

Which of the following statements about metabolic pathways is correct?

Accepted Answer

Metabolic pathways are highly regulated, allowing cells to respond to changes in their environment.

An Introduction to Metabolism (Bio 101, Chapter 8) – Study Notes

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