When urea is heated,it forms biuret,the alkaline solution of which forms $.....$ with $CuSO_4$ solution.

The water-soluble protein is:

Which of the following statements are correct?
$A$) $\alpha$-amino acids present in proteins are $L$-amino acids.
$B$) Amino acids contain both $-NH_2$ and $-COOH$ groups.
$C$) The number of amino groups and carboxylic groups is always the same in amino acids.
$D$) Tyrosine was first obtained from cheese.
Choose the correct alternatives from below:

Which among the following amino acids is $NOT$ synthesized in our body?

Which $\alpha$-amino acid can cross-link peptide chains?

The correct sequence of amino acids present in the tripeptide given below is