How many amino acids are linked together by $(n-1)$ amide bonds?

$A$ substance forms a zwitter ion. It can have which of the following functional groups?

Choose the peptide that matches the abbreviation $Phe-Val-Ala$.

$1.78 \ g$ 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

White precipitate is formed in

Differentiate between globular and fibrous proteins.