Question 1

Which of the following best describes a dehydration reaction in the synthesis of biological polymers?

Accepted Answer

A reaction that removes a water molecule to form a new bond between monomers.

Question 2

Which type of bond links amino acids together in a protein's primary structure?

Accepted Answer

Peptide bond

Question 3

A protein is exposed to high temperature and extreme pH, causing it to lose its native shape and biological activity. What is this process called?

Accepted Answer

Denaturation

Question 4

Which level of protein structure is directly determined by the sequence of amino acids?

Accepted Answer

Primary structure

Question 5

Which of the following is a function of defensive proteins?

Accepted Answer

Protecting against disease by inactivating and destroying viruses and bacteria

Question 6

Which statement about enzymes is TRUE?

Accepted Answer

Enzymes lower the activation energy by stabilizing the transition state.

Question 7

Which of the following best describes the induced fit model of enzyme function?

Accepted Answer

The enzyme changes shape to better fit the substrate upon binding.

Question 8

Which environmental factor is LEAST likely to cause protein denaturation?

Accepted Answer

Neutral pH

Question 9

Which of the following reactions is exergonic?

Accepted Answer

Hydrolysis of ATP to ADP and Pi

Question 10

What is the role of ATP in cellular energy coupling?

Accepted Answer

ATP hydrolysis releases energy to drive endergonic reactions.

Question 11

Which formula correctly represents the change in free energy ($\Delta G$) for a chemical reaction?

Accepted Answer

$\Delta G = G_{products} - G_{reactants}$

Question 12

Which of the following is NOT a way enzymes lower activation energy?

Accepted Answer

Increasing the temperature of the reaction

Question 13

A mutation changes a nonpolar amino acid in the core of a protein to a charged amino acid. What is the most likely effect?

Accepted Answer

The protein may misfold or lose function due to disruption of hydrophobic interactions.

Question 14

Which of the following is TRUE about the second law of thermodynamics in biological systems?

Accepted Answer

Every energy transfer increases the entropy (disorder) of the universe.

Question 15

Which protein function is exemplified by hemoglobin?

Accepted Answer

Transport protein

Question 16

Which of the following is a correct description of quaternary protein structure?

Accepted Answer

The association of multiple polypeptide subunits into a functional protein.

Question 17

Which of the following is a real-life example of enzyme specificity?

Accepted Answer

Hexokinase specifically catalyzes the phosphorylation of glucose.

Question 18

Which of the following best explains why enzymes are effective at body temperature?

Accepted Answer

They lower the activation energy, allowing reactions to proceed rapidly at physiological temperatures.

Question 19

Which of the following is a correct statement about exergonic and endergonic reactions?

Accepted Answer

Exergonic reactions release energy and are spontaneous.

Question 20

A scientist is studying a reaction with a $\Delta G$ of $-3.9$ kcal/mol. What does this value indicate about the reaction?

Accepted Answer

The reaction is exergonic and releases energy.

Proteins, Energy, and Enzymes: Structure, Function, and Biological Roles

Study Guide - Practice Questions