Amino Acids MCQ

• Formation of a peptide bond produces ___ as a byproduct

  water
• In the following peptide, which amino acid is the N-terminus? phenylalanine-alanine-glycine-arginine

  phenylalanine
• Of the 20 standard amino acids, only ___________ is not chiral. The reason is that its side chain ___________.

  glycine; is a hydrogen atom
• The chirality of an amino acid results from the fact that its α carbon:

  is bonded to 4 different chemical groups
• Which statement is correct?

  A)Proteins contain only D amino acids

  B)Proteins contain only L amino acids

  C)Proteins contain both D and L amino acids

  D)None of the above

  B
• How many of the 20 common amino acids have rings in their structures and what are their names?

  • 5
  • proline, phenylalanine, tyrosine, tryptophan, histidine
• Name the aromatic amino acids

  phenylalanine, tyrosine, tryptophan
• What do leucine, isoleucine and valine have in common?

  they have nonpolar aliphatic side chains
• Which amino acids contain a hydroxyl group in their side chain?

  serine, threonine, tyrosine
• Which amino acids contain an acid group in their side chain?

  aspartate, glutamate
• Which amino acids contain an amide group in their side chain?

  asparagine, glutamine
• Which of the following pairs of amino acids is positively charged at a neutral pH?

  lysine, arginine
• Which two amino acids contain a sulfur atom?

  cysteine, methionine
• Which of the following tripeptides would be expected to be the most hydrophobic?

  A)Lys-Tyr-Gly

  B)Lys-Tyr-Ala

  C)Gly-Tyr-Ala

  D)Asp-Tyr-Ala

  E)Asp-Tyr-Gly

  C