Question

Choose the statement that best describes the distribution of amino acid sequence variability in antibody molecules that accounts for the broad antigen-binding repertoire of an antibody, even while the overall structure of the antibody experiences little change?

1) The amino acid sequence of the variable regions of the antibody is highly conserved, while the constant regions show more variability.
2) The amino acid sequence of the constant regions of the antibody is highly conserved, while the variable regions show more variability.
3) The amino acid sequence of both the variable and constant regions of the antibody show high variability.
4) The amino acid sequence of both the variable and constant regions of the antibody is highly conserved.

Answer 1

The amino acid sequence of the constant regions of the antibody is highly conserved, while the variable regions show more variability.

Step-by-step explanation:

The distribution of amino acid sequence variability in antibody molecules that accounts for the broad antigen-binding repertoire of an antibody is best described by option 2: The amino acid sequence of the constant regions of the antibody is highly conserved, while the variable regions show more variability. The constant regions of the antibody have less variation in their amino acid sequences, which allows the overall structure of the antibody to remain relatively unchanged. On the other hand, the variable regions of the antibody have more variability, which enables the antibody to bind to a wide range of antigens. These variable regions are also known as the hypervariable regions or complementarity determining regions (CDRs).