1
Question
The image given below represents an antibody molecule. Identify the parts labelled as A, B and C.
The image given below represents an antibody molecule. Identify the parts labelled as A, B and C.
Open in App
Solution
The correct option is A A - Antigen binding site, B - Light polypeptide chain (L - Chain), C - Heavy polypeptide chain (H - Chain)
Antibodies or immunoglobulins are proteins produced by B lymphocytes that are present in blood and lymph and provide immunity against specific antigens.
Antibodies are ‘Y’ shaped in structure and they have the following parts:
(i) Heavy and light chains - An antibody has 4 peptide chains, two are short and are called light chains and the other two are long and are called heavy chains. H2 (for two heavy chains) and L2 (for two light chains) are the symbols used to represent an antibody molecule (H2L2).
In the image given, C represents the heavy chain and B represents the light chain.
The two heavy chains are linked to each other and to the light chains with the help of disulfide bonds.
(ii) Constant and variable regions - Each peptide chain in the antibody has both constant and variable regions. The amino acid sequence and conformation of the variable region keeps changing according to the shape of the antigen that needs to be eliminated. Hence, the name variable region. The conformation and amino acid sequence of the constant region remains the same.
(iii) Antigen binding site- It is the variable region formed mostly at the upper region in the antibody. The antigen binding site includes the variable regions of both the heavy and the light chain. This site binds with the specific antigen that enters the body and results in the antigen-antibody complex formation, to be recognised by other immune cells. Hence, A represents the antigen binding site.
The image given below depicts the structure of an antibody with labelings.
Antibody molecule
Antibodies or immunoglobulins are proteins produced by B lymphocytes that are present in blood and lymph and provide immunity against specific antigens.
Antibodies are ‘Y’ shaped in structure and they have the following parts:
(i) Heavy and light chains - An antibody has 4 peptide chains, two are short and are called light chains and the other two are long and are called heavy chains. H2 (for two heavy chains) and L2 (for two light chains) are the symbols used to represent an antibody molecule (H2L2).
In the image given, C represents the heavy chain and B represents the light chain.
The two heavy chains are linked to each other and to the light chains with the help of disulfide bonds.
(ii) Constant and variable regions - Each peptide chain in the antibody has both constant and variable regions. The amino acid sequence and conformation of the variable region keeps changing according to the shape of the antigen that needs to be eliminated. Hence, the name variable region. The conformation and amino acid sequence of the constant region remains the same.
(iii) Antigen binding site- It is the variable region formed mostly at the upper region in the antibody. The antigen binding site includes the variable regions of both the heavy and the light chain. This site binds with the specific antigen that enters the body and results in the antigen-antibody complex formation, to be recognised by other immune cells. Hence, A represents the antigen binding site.
The image given below depicts the structure of an antibody with labelings.
Antibody molecule Suggest Corrections
0
Similar questions
View More
Join BYJU'S Learning Program
Explore more
Join BYJU'S Learning Program
