Final answer:
The heavy chain of the immunoglobulin is coded for by chromosome 14 (option A). This segment is crucial for defining the antibody's class or isotype, with different subclasses characterized by their heavy chains. Chromosomes 2 and 22 are responsible for coding the light chains of immunoglobulins.
Step-by-step explanation:
Chromosome Coding for Heavy Chain of Immunoglobulin
The heavy chain of the immunoglobulin (Ig) is coded by chromosome 14. Immunoglobulins are crucial components of the immune system, with heavy chains consisting of variable (V) and constant (C) amino acid sequences. The variable region, VH, is from 1 to 118 amino acids from the N-terminal, and the constant region, CH, is from 119 to 446 amino acids from the N-terminal. The heavy chains are essential for determining the class, or isotype, of an antibody, with different subclasses such as IgG1, IgG2, IgG3, and IgG4, varying by the number of disulfide bonds between the chains.
Light chains, which are coded by either chromosome 2 or 22, also play a significant role in the antibody structure. However, the heavy chains coded by chromosome 14 are responsible for much of the antibodies' functional diversity. An enzyme called DNA recombinase is involved in the recombination process during B cell maturation, creating a unique variable region that can bind to different antigens.