Which type of amino acid is $Methionine$,which initiates protein synthesis?

The most abundant protein in the animal world is

What type of amino acids are phenylalanine and tyrosine,respectively?

Which of the following is a sulphur-containing amino acid?

The spiral configuration of $\alpha$-helix and $\beta$-pleated sheet of polypeptide chains are held together by . . . . . . bonds to form the secondary structure of protein.

Which of the following amino acids is not optically active?