QUIZ 4

Refer to Exhibit 4A. The amino terminal amino acid is:

• Arg

• Cys

• Gln

• Met

• None of these.

Refer to Exhibit 4A. The overall, net ionic charge on this peptide at pH = 7 would be:

• +2

• +1

• 0

• −1

• −2

Hydrogen bonds are most important in this type of structure in proteins:

• primary structure

• secondary structure

• tertiary structure

• quaternary structure

• All of these

The location of prosthetic groups is shown in this level of structure:

• primary structure

• secondary structure

• tertiary structure

• quaternary structure

• All of these

Covalent bonds are important in all these structures, except:

• primary structure

• secondary structure

• tertiary structure

• quaternary structure

• All of these

Which of the following forces are involved in maintaining the primary structure of a protein?

• covalent bonds

• hydrogen bonds

• ionic interactions

• hydrophobic interactions

A single amino substitution can give rise to a malfunctioning protein.

• True

• False

What happens when a protein is denatured?

• Its secondary structure is disrupted but its primary structure remains intact.

• Its primary structure is disrupted but its secondary structure remains intact.

• It is broken apart into its constituent amino acids.

• It becomes all α-helix.

Which of the following amino acids is unlikely to be found in an α-helix?

• phenylalanine

• tryptophan

• proline

• lysine

Which of the following factors tend to destabilize α-helices?

• clusters of amino acids with bulky R-groups

• clusters of amino acids with similarly charged R-groups

• Both of these.

• Neither of these