The Biuret test is not given by which of the following?

Coagulation of egg,on heating,is because of:

How many tripeptides can be prepared by linking the amino acids glycine,alanine and phenylalanine?

$A$ dipeptide,$X$ on complete hydrolysis gives $Y$ and $Z$. $Y$ on treatment with aqueous $HNO_2$ produces lactic acid. On the other hand,$Z$ on heating gives the following cyclic molecule.
Based on the information given,the dipeptide $X$ is:

Identify a side chain $(R)$ group present in serine,an amino acid.

Consider the following statements:
Statement-$I$: Lysine and arginine are essential and basic amino acids.
Statement-$II$: Leucine and phenylalanine are non-essential and neutral amino acids.