The helical structure of protein is stabilised by

The incorrect statement about denaturation of proteins is

$1.78 \ g$ of an optically active $L$-amino acid $(A)$ is treated with $NaNO_{2} / HCl$ at $0^{\circ}C$. $448 \ cm^{3}$ of nitrogen at $STP$ is evolved. $A$ sample of protein has $0.25 \%$ of this amino acid by mass. The molar mass of the protein is

Which of the following is not true about the denaturation of protein?

When $HNO_3$ is dropped into the palm and washed with water,it turns yellow. The above yellow colour is due to:

Which from the following is an essential amino acid?