Which of the following amino acids is involved in the formation of $Heme$?

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?

Select the correct match for $X$ and $Y$:

Column $X$	Column $Y$
$(1)$ Primary protein	$(P)$ Globular or fibrous form
$(2)$ Secondary protein	$(Q)$ Three-dimensional arrangement of a single polypeptide chain
$(3)$ Tertiary protein	$(R)$ Gene-controlled
$(4)$ Quaternary protein	$(S)$ Helical or pleated sheet form

Which group in the structure of an amino acid is basic?

$S$ - Statement: Proteins are called conjugated proteins when they are associated with substances other than amino acids.
$R$ - Reason: Chlorophyll is essential for photosynthesis.