Question 1

Which of the following statements best explains why amino acids are soluble in water?

Accepted Answer

The charges on their amino and carboxyl groups allow them to interact with water molecules.

Question 2

A scientist discovers a new amino acid with a side chain containing only carbon and hydrogen atoms. Which property is this amino acid most likely to exhibit?

Accepted Answer

It will be hydrophobic and avoid interacting with water.

Question 3

Which of the following best describes the formation of a peptide bond?

Accepted Answer

A condensation reaction between the carboxyl group of one amino acid and the amino group of another.

Question 4

A mutation changes a single amino acid in the primary structure of hemoglobin, causing the protein to stick to others and form fibers. Which level of protein structure is directly affected by this mutation?

Accepted Answer

Primary structure

Question 5

Which type of interaction is NOT involved in stabilizing the tertiary structure of a protein?

Accepted Answer

Hydrogen bonding between backbone atoms

Question 6

A protein is found to consist of two identical polypeptide subunits. What is the best description of its quaternary structure?

Accepted Answer

It is a homodimer.

Question 7

Which of the following scenarios would most likely result in a protein becoming denatured?

Accepted Answer

Exposure to high temperatures that disrupt hydrogen bonds and hydrophobic interactions

Question 8

Which of the following best explains why prions are considered 'infectious' proteins?

Accepted Answer

They induce normal proteins to adopt an abnormal, disease-causing conformation.

Question 9

Which of the following is a function of molecular chaperones in cells?

Accepted Answer

They facilitate proper folding of newly synthesized proteins.

Question 10

A protein’s secondary structure is stabilized primarily by which type of bond?

Accepted Answer

Hydrogen bonds between backbone carbonyl and amino groups

Question 11

Which of the following best describes the directionality of a polypeptide chain?

Accepted Answer

It is synthesized from the N-terminus to the C-terminus.

Question 12

Which of the following is NOT a function performed by proteins in cells?

Accepted Answer

Storing genetic information

Question 13

A researcher is studying a protein that only becomes functional after binding to a specific small molecule. What does this observation suggest about the protein’s folding?

Accepted Answer

The protein’s folding is regulated and may require binding to other molecules to achieve its active conformation.

Question 14

Which of the following best describes the role of the active site in an enzyme?

Accepted Answer

It is the location where substrates bind and undergo a chemical reaction.

Question 15

A protein is found to have a single polypeptide chain with several alpha-helices and beta-pleated sheets. Which levels of structure are present in this protein?

Accepted Answer

Primary, secondary, and tertiary

Question 16

Which of the following equations correctly represents the condensation reaction that forms a peptide bond?

Accepted Answer

$$ 	ext{Amino acid}_1 + 	ext{Amino acid}_2 ightarrow 	ext{Dipeptide} + H_2O $$

Question 17

Which of the following R-group characteristics would most likely be found in the interior of a globular protein in aqueous solution?

Accepted Answer

Nonpolar and hydrophobic

Question 18

A patient is diagnosed with a disease caused by the accumulation of misfolded proteins in the brain. Which of the following is the most likely explanation for the disease mechanism?

Accepted Answer

Prions have induced normal proteins to adopt an abnormal conformation.

Question 19

Which of the following best explains why a single amino acid substitution can have a dramatic effect on protein function?

Accepted Answer

It can alter the protein’s primary structure, which in turn affects all higher levels of structure and function.

Protein Structure and Function: Study Notes for Biology Students

Study Guide - Practice Questions

Study Guide - Flashcards