Q: An enzyme catalyzes the conversion of substrate A to product B. If the enzyme is denatured by high temperature, what is the most likely outcome?

The enzyme will lose its specific shape and become inactive.

Q: Which of the following best explains why enzymes lower the activation energy of a reaction?

They provide a site where reactants are brought together and stabilized.

Q: A competitive inhibitor affects an enzyme by:

Binding to the active site and preventing substrate binding.

Q: Which factor would most likely increase the rate of an enzyme-catalyzed reaction up to a certain point?

Increasing substrate concentration

Q: Which statement about vitamins is correct?

Vitamins often act as coenzymes or precursors to coenzymes in metabolic reactions.

Q: A metabolic pathway consists of three enzyme-catalyzed reactions. If enzyme 2 is nonfunctional, what will happen?

The substrate for enzyme 2 will accumulate.

Q: Which of the following is an example of allosteric regulation?

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

Q: Which of the following best describes a catabolic reaction?

Large molecules are broken down into smaller ones, releasing energy.

Question 1

Which statement best describes the First Law of Thermodynamics as it applies to biological systems?

Accepted Answer

Energy is conserved; it can be transformed from one form to another but cannot be created or destroyed.

Question 2

A cell breaks down glucose in a series of reactions, releasing heat and increasing entropy. Which law of thermodynamics does this process illustrate?

Accepted Answer

Second Law of Thermodynamics

Question 3

Which of the following reactions is most likely to be exergonic?

Accepted Answer

Hydrolysis of ATP to ADP and $\mathrm{P_i}$

Question 4

Consider the Gibbs free energy equation: $\Delta G = \Delta H - T\Delta S$. Which condition will make a reaction spontaneous?

Accepted Answer

$\Delta G < 0$

Question 5

An enzyme catalyzes the conversion of substrate A to product B. If the enzyme is denatured by high temperature, what is the most likely outcome?

Accepted Answer

The enzyme will lose its specific shape and become inactive.

Question 6

Which of the following best explains why enzymes lower the activation energy of a reaction?

Accepted Answer

They provide a site where reactants are brought together and stabilized.

Question 7

A competitive inhibitor affects an enzyme by:

Accepted Answer

Binding to the active site and preventing substrate binding.

Question 8

Which factor would most likely increase the rate of an enzyme-catalyzed reaction up to a certain point?

Accepted Answer

Increasing substrate concentration

Question 9

Which statement about vitamins is correct?

Accepted Answer

Vitamins often act as coenzymes or precursors to coenzymes in metabolic reactions.

Question 10

A metabolic pathway consists of three enzyme-catalyzed reactions. If enzyme 2 is nonfunctional, what will happen?

Accepted Answer

The substrate for enzyme 2 will accumulate.

Question 11

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 shape.

Question 12

Which of the following best describes a catabolic reaction?

Accepted Answer

Large molecules are broken down into smaller ones, releasing energy.

Question 13

Which vitamin is essential for the metabolism of glucose and amino acids and acts as a coenzyme?

Accepted Answer

Vitamin B

Question 14

If a cell needs to decrease entropy locally, what must it do according to the laws of thermodynamics?

Accepted Answer

Spend energy to organize molecules.

Question 15

Which of the following is true about noncompetitive inhibition?

Accepted Answer

The inhibitor binds elsewhere on the enzyme, changing its shape and reducing activity.

Question 16

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

Accepted Answer

The end product of a metabolic pathway binds to an enzyme early in the pathway, decreasing its activity.

Question 17

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

Accepted Answer

Enzymes have active sites with shapes complementary to their substrates.

Question 18

Which of the following would most likely result from a mutation that changes the shape of an enzyme's active site?

Accepted Answer

The enzyme will lose its ability to bind its substrate.

Question 19

Which of the following equations correctly represents the relationship between free energy, enthalpy, and entropy in a biological system?

Accepted Answer

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

Question 20

Which of the following is NOT a factor that influences the rate of enzyme-catalyzed reactions?

Accepted Answer

Color of the substrate

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

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