Identify the essential amino acids from the following:
$A$) Leucine
$B$) Tyrosine
$C$) Cysteine
$D$) Histidine

How many amino acids are present in insulin?

Identify the correct set of functional groups present in aspartame,an artificial sweetener.

$A$ protein '$X$' with a molecular weight of $70,000 \ u$,on hydrolysis gives amino acids. One of these amino acids is:

What are the hybridisation of the carbon atoms labeled $C_1$ and $C_2$,respectively in glycine?

Protein found in a biological system with a unique three-dimensional structure and biological activity is called a native protein. When a protein in its native form is subjected to a physical change like a change in temperature or a chemical change like a change in $pH$,denaturation of proteins takes place. Explain the cause.