Question

Which of the following is not a classification of proteins?
A Enzymes
B Antibodies
C Antigens
D Hormones

Answer 1

Hint: Proteins being a complex compound composed of amino acid building blocks can be classified on the basis of chemical composition, shape, and function. Proteins based on chemical composition are simple proteins and conjugated proteins. Classification of proteins on the basis of shape are fibrous, globular, and intermediate proteins. Three of all four options are classified on the basis of biological functions.

Complete Step by Step Solution:
All the enzymes are proteins, but the converse may not be true, because all the enzymes form from the complex arrangements of a large number of amino acids. But all proteins do not have the tendency to attach a substrate (any drug) over its surface (enzyme activity ) and show biological functions.

The other function of protein is to activate enzymes with the help of hormones, which are itself prepared by proteins in the endocrine cell. These hormones bind with proteins at the time of need outside the cell and then send signals to another message sender to activate the enzymes for healthy biological functioning in the body.

There is also another protein classified on the basis of biological functions, known as antibody (Y-shaped protein). There are proteins which themselves are synthesised by the immune system against unfavourable substances coming from outside whose intention is to harm biological functioning, known as Antigens for example harmful bacteria, parasites, fungi and many others.
Thus, the correct option is C.

Note: Antigens are the substances which force the body to make a strong immune system, and thus, the body generates antibodies. Indirectly antigens are generators or producers of antibodies (which is a protein). Antigens can be proteins, carbohydrates, nucleic acid, polysaccharides and lipids (insoluble in water).