The central carbon atom in an amino acid is called:

• β-carbon

• γ-carbon

• α-carbon

• δ-carbon

What determines the unique chemical properties of an amino acid?

• Amino group

• Carboxyl group

• Hydrogen atom

• R group

At physiological pH (~7.4), amino acids exist predominantly in what form?

• Protonated

• Deprotonated

• Zwitterionic

• Neutral

Which amino acid is achiral?

• Glycine

• Alanine

• Serine

• Tryptophan

The amino acids serine, threonine, and cysteine are classified as:

• Nonpolar

• Polar, uncharged

• Acidic

• Basic

Which of the following is an aromatic amino acid?

• Glycine

• Phenylalanine

• Leucine

• Valine

The isoelectric point (pI) of an amino acid refers to:

• The pH at which it is most acidic

• The pH at which it is most basic

• The pH at which it has no net charge

• The pH at which it dissolves completely

Which amino acid contains a sulfur atom?

• Methionine

• Lysine

• Aspartic acid

• Histidine

Amino acids with positively charged side chains at physiological pH are:

• Glutamine, Tyrosine

• Aspartate, Glutamate

• Lysine, Arginine, Histidine

• Alanine, Glycine

Amino acids like leucine and valine are classified as:

• Acidic

• Nonpolar

• Polar, uncharged

• Aromatic