Amino Acids (ht Only) (GCSE Chemistry)

At a pH below the isoelectric point (pI) of an amino acid, what is the predominant net charge on the molecule?

Which analytical change would you expect when an amino acid sample is titrated, passing its isoelectric point pI?

Which description best fits the role of an amino acid side chain in determining protein function?

During Edman degradation the N-terminal amino acid of a polypeptide is sequentially removed for identification. Which functional group does Edman chemistry target for cleavage?

Which of the following best describes formation of a peptide bond between two amino acids mechanistically?

Which amino acid is unique because it lacks a chiral a-carbon and therefore is not optically active?

Which statement about side chains of acidic amino acids (aspartic and glutamic acid) is true at physiological pH (~7.4)?

Which pair of pKa values is most consistent with a neutral amino acid that has an a-carboxyl pKa ˜ 2.2 and an a-amino pKa ˜ 9.4?

Amino acids can act as buffers. Around which pH value does an amino acid buffer strongly?

Which process describes the hydrolysis of a polypeptide back to its constituent amino acids?

Which reagent gives a purple (Ruhemann’s purple) colour when it reacts with free amino acids, and is used to detect amino acids in chromatography spots?