Final answer:
The TCR and BCR are two types of antigen receptors found on T cells and B cells respectively. The TCR recognizes antigens presented on MHC molecules, while the BCR can directly bind to antigens.
Step-by-step explanation:
The T cell receptor (TCR) and the Ig (BCR) are two types of antigen receptors found on different types of immune cells. The TCR is found on T cells, while the BCR is found on B cells. Both the TCR and BCR recognize antigens, but they do so in different ways.
The TCR recognizes antigens that are presented on the surface of cells by molecules called major histocompatibility complex (MHC) molecules. The TCR binds to the antigen-MHC complex and triggers a response from the T cell.
In contrast, the BCR recognizes antigens directly. The BCR can bind to free antigens in the body or to antigens displayed on the surface of pathogens. The BCR does not require the involvement of MHC molecules.