Question 1

Which of the following best describes the chemical reaction that forms a peptide bond between two amino acids?

Accepted Answer

A condensation reaction that releases a water molecule when the carboxyl group of one amino acid reacts with the amino group of another.

Question 2

A mutation causes a single amino acid change in the primary structure of hemoglobin, resulting in sickle cell disease. This is an example of how:

Accepted Answer

A change in the primary structure can radically alter protein function.

Question 3

Which of the following R-groups would most likely be found in the interior of a globular protein in an aqueous environment?

Accepted Answer

A nonpolar R-group such as leucine.

Question 4

What type of bond is primarily responsible for stabilizing the secondary structure of proteins?

Accepted Answer

Hydrogen bonds between the carbonyl group of one amino acid and the amino group of another.

Question 5

Which of the following statements about protein folding is TRUE?

Accepted Answer

Molecular chaperones can assist in proper protein folding by preventing inappropriate interactions.

Question 6

A protein is found to consist of two identical polypeptide subunits. This protein is best described as a:

Accepted Answer

Homodimer

Question 7

Which of the following best explains why enzymes are effective biological catalysts?

Accepted Answer

They hold substrates in a precise orientation at the active site, lowering activation energy.

Question 8

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

Accepted Answer

Hydrogen bonding between backbone atoms only

Question 9

A researcher denatures a protein by heating it. Which level(s) of protein structure are most likely disrupted?

Accepted Answer

Secondary, tertiary, and quaternary structures

Question 10

Which of the following best describes a prion?

Accepted Answer

A misfolded protein that can induce normal proteins to adopt an abnormal conformation

Question 11

Given the following amino acid side chain: $$\mathrm{CH_2SH} ($$cysteine), which type of bond can it form to stabilize protein structure?

Accepted Answer

Disulfide bond

Question 12

Which of the following is a function of proteins in cells?

Accepted Answer

All of the above

Question 13

A protein's primary structure is determined by:

Accepted Answer

The sequence of amino acids from N-terminus to C-terminus

Question 14

Which of the following amino acids would you expect to find on the surface of a protein embedded in the cell membrane?

Accepted Answer

Leucine

Question 15

Which of the following best explains why nonpolar amino acids are hydrophobic?

Accepted Answer

They lack charged or polar groups, so they do not interact favorably with water.

Question 16

Which of the following is TRUE about the directionality of a polypeptide chain?

Accepted Answer

By convention, the sequence is written from N-terminus to C-terminus.

Question 17

Which of the following best describes a macromolecular machine?

Accepted Answer

A complex of multiple proteins that carry out a specific function

Question 18

Which of the following is NOT a possible interaction that stabilizes tertiary protein structure?

Accepted Answer

Peptide bonds between amino acids

Question 19

Which of the following best explains why denatured proteins lose their function?

Accepted Answer

Denaturation disrupts the three-dimensional shape required for function.

Question 20

Which of the following is a direct result of the hierarchical nature of protein structure?

Accepted Answer

The primary structure determines the secondary, tertiary, and quaternary structures.

Protein Structure and Function: Study Notes

Study Guide - Practice Questions