Total number of essential amino acids among the given list of amino acids is . . . .
Arginine,Phenylalanine,Aspartic acid,Cysteine,Histidine,Valine,Proline

Describe the term $D$ and $L$ configuration used for the amino acids with examples.

Treatment of compound $O$ ($1,2-$diethylbenzene) with $KMnO_4 / H^{+}$ gives $P$ (phthalic acid),which on heating with ammonia gives $Q$ (phthalamide). The compound $Q$ on treatment with $Br_2 / NaOH$ produces $R$ ($o-$phenylenediamine). On strong heating,$Q$ gives $S$ (phthalimide),which on further treatment with ethyl $2-$bromopropanoate in the presence of $KOH$ followed by acidification,gives a compound $T$.
$(1)$ The compound $R$ is
$(2)$ The compound $T$ is
$(A)$ glycine
$(B)$ alanine
$(C)$ valine
$(D)$ serine
Identify the correct options for $(1)$ and $(2)$.

In the given reaction: $CH_3-CHCl-COOH \xrightarrow[(ii) H_2O]{(i) NH_3 (1 \text{ mole})} [X]$. Product $[X]$ will be:

Denaturation of proteins leads to loss of its biological activity by

Which of the following amino acids will give a violet-coloured complex with neutral ferric chloride solution?