The part of an antibody molecule that binds the antigen is located in the
- A. constant region of the heavy chains
- B. Fc tail
- C. carbohydrate side chains
- D. variable region at the tips of the two arms
Explanation
The amino acid sequence of the variable region changes from one antibody to another, shaping the binding site, while the constant tail determines class functions such as binding phagocytes. Structure and specificity meet at the tips.