Hydrolysis of proteins gives

The correct structure of product $P$ in the following reaction is
$Asn-Ser + (excess) (CH_3CO)_2O \xrightarrow{NEt_3} P$

The total number of amino acids present in insulin is

Explain the types of protein structures based on the provided image.

Which among the following compounds contains both,amino and carboxyl groups in it?

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