$HC\equiv CH$ $\xrightarrow[HgSO_4]{H_2SO_4} (A)$ $\xrightarrow[(1) NH_3 + HCN]{(2) H_3O^{\oplus}} (B);$ The product $(B)$ of the given reaction is:

In an amino acid,the carboxylic group ionises at $pH = 2.56$ $(pK_{a_1})$ and the ammonium ion ionises at $pH = 9.38$ $(pK_{a_2})$. The isoelectric point of the amino acid is at:

Match List-$I$ with List-$II$.

List-$I$ (Natural amino acid)	List-$II$ (Code)
$A$. Glutamic acid	$I$. $Q$
$B$. Glutamine	$II$. $W$
$C$. Tyrosine	$III$. $E$
$D$. Tryptophan	$IV$. $Y$

The cell membrane is primarily composed of ...........

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 of the following is an essential amino acid?