Which one is the most abundant protein in the animal world?

Which of the following bonds does not participate in the formation of the quaternary structure of proteins?

Match the following.

Column-$I$	Column-$II$
$A$. Trypsin	$1$. Intercellular ground substance
$B$. $GLUT-4$	$2$. Hormone
$C$. Insulin	$3$. Enzyme
$D$. Collagen	$4$. Enables glucose transport into cells

Select the correct option for the following matches:

$(1)$ Contractile protein	$(a)$ Immunoglobulin
$(2)$ Protein produced by cells	$(b)$ Globular protein
$(3)$ Protein that gives color to the iris	$(c)$ Actin
$(4)$ Protein for muscular movement	$(d)$ Melanin

The $pH$ value of a solution in which a polar amino acid does not migrate under the influence of an electric field is called:

Which of the following amino acids is not optically active?