Thiol group is present in:

Glycylalanine is a dipeptide of which amino acids?

Which compound can exist in a dipolar (zwitter ion) state?

$1.$ Glycylglycine
$2.$ Alanylalanine
$3.$ Glycylalanine
$4.$ Alanylglycine
The dipeptides which may be obtained from the amino acids glycine and alanine are

Assertion : Proteins on hydrolysis produce amino acids.
Reason : Amino acids contain $-NH_2$ and $-COOH$ groups.

Which one of the following statements is not correct?