Which is the $C$-terminal residue in glycyl alanine?

The main structural feature of proteins is

The $pH$ at the isoelectric point of three amino acids are given as follows:

Amino acid	$pH$ at Isoelectric point
$(Amino \ acid)_{I}$	$6$
$(Amino \ acid)_{II}$	$9.8$
$(Amino \ acid)_{III}$	$3.9$

$(Amino \ acid)_{II}$ is . . . . . . ?

Which of the following is a basic amino acid?

Among the following,the essential amino acid is

$1.78 \ g$ of an optically active $L$-amino acid $(A)$ is treated with $NaNO_{2} / HCl$ at $0^{\circ}C$. $448 \ cm^{3}$ of nitrogen at $STP$ is evolved. $A$ sample of protein has $0.25 \%$ of this amino acid by mass. The molar mass of the protein is