Question 1

Which part of an amino acid is responsible for its unique chemical properties and interactions in proteins?

Accepted Answer

The side chain (R group)

Question 2

What type of bond links amino acids together in a polypeptide chain?

Accepted Answer

Peptide bond

Question 3

A protein’s primary structure is best described as:

Accepted Answer

The sequence of amino acids in the polypeptide

Question 4

Which of the following interactions is NOT involved in stabilizing a protein’s tertiary structure?

Accepted Answer

Peptide bonds

Question 5

Hemoglobin is an example of a protein with which level of structure?

Accepted Answer

Quaternary structure

Question 6

A single amino acid substitution in the primary structure of hemoglobin can lead to which disease?

Accepted Answer

Sickle-cell disease

Question 7

Which of the following best explains why proteins denature at high temperatures?

Accepted Answer

High temperatures disrupt non-covalent interactions such as hydrogen bonds and hydrophobic interactions

Question 8

Which structural level of a protein is directly affected by changes in pH, salt concentration, or temperature?

Accepted Answer

Tertiary and quaternary structure

Question 9

If a protein is denatured, which of the following is most likely to occur?

Accepted Answer

The protein will lose its biological function

Question 10

Which of the following is a covalent bond that can reinforce the tertiary structure of a protein?

Accepted Answer

Disulfide bridge

Question 11

A protein’s function is most directly determined by:

Accepted Answer

Its three-dimensional structure

Question 12

Which of the following best describes the secondary structure of a protein?

Accepted Answer

Coils and folds formed by hydrogen bonds between backbone constituents

Question 13

Which of the following is a real-world consequence of protein misfolding?

Accepted Answer

Diseases such as Alzheimer’s and mad cow disease

Question 14

Which of the following statements about peptide bonds is correct?

Accepted Answer

Peptide bonds are formed by dehydration synthesis between the amino group of one amino acid and the carboxyl group of another

Question 15

Which formula correctly represents the formation of a peptide bond between two amino acids?

Accepted Answer

$\mathrm{Amino\ acid}_1 + \mathrm{Amino\ acid}_2 \rightarrow \mathrm{Dipeptide} + H_2O$

Question 16

Which of the following best explains why sickle-cell disease affects the shape and function of red blood cells?

Accepted Answer

A single amino acid substitution in the primary structure of hemoglobin

Question 17

Which of the following is most likely to occur if a protein is exposed to a denaturing agent and then the agent is removed?

Accepted Answer

The protein may refold and regain function, but this is not always possible

Question 18

Which of the following is a correct statement about the quaternary structure of proteins?

Accepted Answer

It results from the association of two or more polypeptide chains

Question 19

Which of the following is a real-life example of a protein with quaternary structure?

Accepted Answer

Collagen, consisting of three polypeptides coiled like a rope

Question 20

Which of the following best describes the role of chaperone proteins (such as HSP70) in cells?

Accepted Answer

They assist in the proper folding of other proteins, especially under stress conditions

Chapter 5.4

Study Guide - Practice Questions