Which is NOT Part of a Description of an Antibody

Question

Which is NOT part of a description of an antibody molecule?
A)contains two light chains and two heavy chains
B)contains an antigen-binding site on each arm
C)contains a constant and a variable region on each chain
D)forms an X-shaped protein molecule

Accepted Answer

Antibody molecules are Y-shaped, not X-shaped. They consist of two heavy chains and two light chains, with antigen-binding sites on each arm and both constant and variable regions on each chain.