Question

Which immunoglobulin is largest in size
A) IgA
B) IgD
C) IgE
D) IgM

Answer 1

Hint:Immunoglobulins, also known as antibodies, are glycoprotein molecules produced by plasma cells (white blood cells).Largest immunoglobulin has more light and heavy chains.

Complete answer:
There are total 5 types of immunoglobulins -IgA IgE IgD IgM IgG
which help in fighting with antigens and provide immunity to the body.They all are distinguished by number of heavy and light chains,so they have more binding sites for an antigen.They trap the antigen by various processes like opsonization agglutination etc.by forming an antibody- antigen complex thereby destroying the antigen.IgM is the largest antibody as it is a pentamer which has 10 antigen binding sites ,therefore it is more efficient and gives strong immune response. It is the first antibody to reach the site of infection.They are found majorly in blood and lymph,where most of the antigens are present.These antibodies are formed by plasma B cells to make the body free from pathogens.

Hence the correct answer is option ‘D’.

Note:Antibodies are made up of large protein molecules.IgA is present in milk and saliva ,all types of fluids.IgE is the antibody which shows its effect in allergic conditions.IgD Is the mirror antibody and it has a very limited role in body and it is a monomer.