Final answer:
Antibody molecules can be cleaved into two functionally distinct fragments: the Fab regions, which are involved in antigen binding, and the Fc region, which interacts with immune cells.
Step-by-step explanation:
The two functionally distinct fragments that antibody molecules can be readily cleaved into are the Fab regions and the Fc region.
The Fab region, or "fragment of antigen binding," consists of the two 'arms' of the Y-shaped antibody molecule. Each arm contains a variable region, which determines the epitope to which the antibody can bind. The binding of an antigen to the Fab region is essential for functions such as neutralization of pathogens, agglutination, and antibody-dependent cell-mediated cytotoxicity.
On the other hand, the Fc region is formed by the lower part of the Y-shaped structure, resulting from the two heavy chains coming together. This region is recognized by Fc receptors on certain cells of the immune system, which allows these cells to bind to antibody-coated pathogens, increasing the specificity and efficiency of the immune response.