The correct structure of Rhumann's Purple,the compound formed in the reaction of ninhydrin with proteins is :

Identify the pair of reactants that upon reaction,with elimination of $HCl$,will give rise to the dipeptide $Gly-Ala$.

Which of the following structures of proteins represents its constitution?

The substituents $R_1$ and $R_2$ for nine peptides are listed in the table given below. How many of these peptides are positively charged at $pH = 7.0$?

Peptide	$R_1$	$R_2$
$I$	$H$	$H$
$II$	$H$	$CH_3$
$III$	$CH_2COOH$	$H$
$IV$	$CH_2CONH_2$	$(CH_2)_4NH_2$
$V$	$CH_2CONH_2$	$CH_2CONH_2$
$VI$	$(CH_2)_4NH_2$	$(CH_2)_4NH_2$
$VII$	$CH_2COOH$	$CH_2CONH_2$
$VIII$	$CH_2OH$	$(CH_2)_4NH_2$
$IX$	$(CH_2)_4NH_2$	$CH_3$

Which of the statements about "Denaturation" given below are correct?
$1.$ Denaturation of proteins causes loss of secondary and tertiary structures of the protein.
$2.$ Denaturation leads to the conversion of double strand of $DNA$ into single strand.
$3.$ Denaturation affects primary structure which gets distorted.

The naturally occurring amino acid that contains only one basic functional group in its chemical structure is