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 between the amino group of one amino acid and the carboxyl group of another, releasing water.

Question 2

Given the following amino acid side chain: $$\mathrm{CH_2SH}$$, which type of interaction is it most likely to participate in within a protein's tertiary structure?

Accepted Answer

Disulfide covalent bonding

Question 3

A mutation changes a glutamic acid residue (charged, polar) in hemoglobin to valine (nonpolar). What is the most likely effect on the protein?

Accepted Answer

The protein may aggregate due to hydrophobic interactions, potentially causing disease.

Question 4

Which of the following statements about protein structure is correct?

Accepted Answer

Tertiary structure is stabilized by hydrogen bonds, ionic bonds, hydrophobic interactions, van der Waals forces, and disulfide bridges.

Question 5

Which of the following best explains why proteins can perform such a wide variety of cellular functions?

Accepted Answer

The diversity of R-groups allows for a vast array of protein shapes and chemical properties.

Question 6

Which of the following is a property of an amino acid with a side chain containing only carbon and hydrogen atoms?

Accepted Answer

It is hydrophobic and does not interact with water.

Question 7

A protein is denatured by heat. Which level(s) of protein structure are most likely disrupted?

Accepted Answer

Secondary, tertiary, and quaternary structures

Question 8

Which of the following best describes the role of molecular chaperones in cells?

Accepted Answer

They assist in the proper folding of newly synthesized proteins.

Question 9

Which of the following is true regarding the directionality of a polypeptide chain?

Accepted Answer

The C-terminus has a free carboxyl group.

Question 10

Which of the following scenarios best illustrates the importance of protein folding for function?

Accepted Answer

A denatured enzyme loses its catalytic activity.

Question 11

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

Accepted Answer

Peptide bonds between amino acids

Question 12

A protein is composed of two identical polypeptide subunits. What is the best term for this structure?

Accepted Answer

Homodimer

Question 13

Which of the following best describes a prion?

Accepted Answer

A misfolded protein that can induce normal proteins to misfold, causing disease.

Question 14

Which of the following is a direct result of the ionization of amino and carboxyl groups in amino acids in water?

Accepted Answer

Amino acids are more soluble and can participate in chemical reactions.

Question 15

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 16

Which of the following amino acids would you expect to find in the interior of a globular protein in an aqueous environment?

Accepted Answer

Leucine

Question 17

Which of the following is a consequence of a single amino acid substitution in the primary structure of a protein?

Accepted Answer

It can have no effect, or it can radically alter the protein's function.

Question 18

Which of the following best describes the relationship between protein structure and function?

Accepted Answer

The specific three-dimensional shape of a protein determines its function.

Protein Structure and Function: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards