Identify the amino acid which has $-NH_2$,$-CO_2H$ and $-CONH_2$ groups.

Which of the following is $NOT$ a basic amino acid?

Which of the following molecules is eliminated during peptide bond formation?

Among the $\alpha$-amino acids - threonine,tyrosine,methionine,arginine and tryptophan,those which contain an aromatic group in their side chain are

Which of the following statements about proteins is not true?

The isoelectric point of alanine is $pH = 6$. At which $pH$ will the maximum concentration of the zwitterion of alanine be present?