Biochemistry: Proteins

Which of the following groups are found in every standard amino acid?

• Phosphate group and hydroxyl group

• Amino group and phosphate group

• Amino group and carboxyl group

• Hydroxyl group and carboxyl group

What makes glycine unique among the 20 standard amino acids?

• It has a ring structure

• It lacks a chiral alpha carbon

• It is positively charged at physiological pH

• It is always phosphorylated in cells

Which amino acid contains a sulfhydryl group capable of forming disulfide bonds?

• Tyrosine

• Histidine

• Serine

• Cysteine

What type of bond forms between two amino acids in a protein?

• Hydrogen bond

• Peptide bond

• Disulfide bond

• Ionic bond

What is the net result of peptide bond formation between two amino acids?

• Addition of a water molecule

• A hydrolysis reaction

• Elimination of a water molecule (condensation reaction)

• Loss of a carbon atom

Which amino acid often introduces bends or kinks in polypeptides due to its rigid ring structure?

• Glycine

• Proline

• Alanine

• Serine

How many amino acids make up one full turn of an alpha helix?

• 3.0

• 3.8

• 3.6

• 4.2

Beta-pleated sheets are primarily stabilized by:

• Hydrophobic interactions

• Hydrogen bonds between backbone atoms

• Ionic bonds between side chains

• Peptide bonds

Which amino acid is most commonly found at the centre of collagen’s triple helix?

• Proline

• Glycine

• Cysteine

• Tyrosine

What technique did Frederick Sanger use to determine the first protein sequence?

• Edman degradation

• Mass spectrometry

• Gel electrophoresis

• NMR