DPP 9.1

The structure of the glutathione is

Explain the function of glutathione as a free radical scavenger in the cells.

A nonapeptide of molecular formula, $\mathrm{Arg},\mathrm{Gly},{\mathrm{Phe}}_2, \mathrm{Ser}, {\mathrm{Pro}}_3$, has arginine $\left(\mathrm{Arg}\right)$ residue on both ends. On partial hydrolysis, it gives the following peptides.
$\mathrm{Phe}. \mathrm{Ser} + \mathrm{Phe}. \mathrm{Arg} + \mathrm{Pro}. \mathrm{Pro}. + \mathrm{Arg}. \mathrm{Pro} + \mathrm{Pro}. \mathrm{Gly}. \mathrm{Phe} + \mathrm{Ser}. \mathrm{Pro}. \mathrm{Phe}$

The correct statement(s) about the following sugars $\mathrm{X}$ and $\mathrm{Y}$ is/are:

Which forms Zwitter ion$?$

Alanine forms Zwitter ion, which exists as:

The correct statements about above structure of glucose are:

$\mathrm{D}$-Mannose differs from $\mathrm{D}$-glucose in its stereochemistry at $\mathrm{C}-2 .$ The pyranose form of $\mathrm{D}$-Mannose is:

The correct structure of glycine at the given $\mathrm{pH}$ is: