Final answer:
The CDR1 and CDR2 loops are part of the T-cell receptor's antigen-binding site, involved in recognizing specific antigens. The TCR consists of variable and constant regions across its two peptide chains, with specificity established through genetic rearrangement.
Step-by-step explanation:
The Complementarity-Determining Region 1 (CDR1) and Complementarity-Determining Region 2 (CDR2) loops of the T-cell receptor (TCR) form parts of the antigen-binding site, which is crucial for the immune system's ability to recognize and respond to antigens. The TCR is similar to antibodies in that it has both a variable region, which determines the antigen specificity, and a constant region which is less variable. Each T cell produces only one type of receptor and thus is specific for a single particular antigen. The TCR is made up of two peptide chains, the alpha and beta chains, which span the cell membrane and project their variable binding regions into extracellular space to bind processed antigens associated with MHC molecules. Diversity in TCR is generated through genetic rearrangement of variable (V), diversity (D), and joining (J) segments, similar to that of B-cell receptors (BCR).