Question

Which areas of MHC Class I molecules are polymorphic?

A) α1 and α2 domains
B) α3 domain
C) β2-microglobulin
D) αβ domains

Answer 1

The areas of MHC Class I molecules that are polymorphic are the α1 and α2 domains.

Step-by-step explanation:

The areas of MHC Class I molecules that are polymorphic are the α1 and α2 domains. MHC Class I molecules are composed of a longer α protein chain coupled with a smaller β₂ microglobulin protein, and only the α chain spans the cytoplasmic membrane. The α chain of the MHC I molecule folds into three separate domains: α₁, α₂, and α₃. Therefore, the polymorphic regions are the α₁ and α₂ domains.