Which of the following amino acids is achiral?

Which among the following amino acids has the lowest molar mass?

Which among the following is a globular protein?

Biuret test is used for the detection of

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.

$A$ tetrapeptide has a $-COOH$ group on alanine. This produces glycine $(Gly)$,valine $(Val)$,phenylalanine $(Phe)$,and alanine $(Ala)$ on complete hydrolysis. For this tetrapeptide,the number of possible sequences (primary structures) with the $-NH_2$ group attached to a chiral center is: