Final answer:
The statement is false; CDR1 and CDR2 contribute to antigen recognition by the TCR but the specificity for the peptide-MHC complex involves all CDRs, with CDR3 playing a crucial role. The correct option is b.
Step-by-step explanation:
The statement that CDR1 and CDR2 (encoded by the V gene segment) recognize and interact with the peptides loaded on the MHC molecule is false. The CDR1 and CDR2 are indeed part of the variable region of the T-cell receptor (TCR), which is responsible for the recognition of antigens.
However, the specificity for the peptide-MHC complex is determined by all complementarity-determining regions (CDRs) of the TCR, including CDR3, which plays a pivotal role in this interaction as well.
The V gene segment contributes to the genetic diversity required for the production of TCRs, ensuring recognition of a wide array of antigens through genetic rearrangement.
Antigen processing and presentation involve the antigen being presented by MHC molecules on the surface of antigen-presenting cells, forming a complex which is then recognized by TCRs on T-cells. This complex recognition process is a key component of the immune response. Option b. is the correct one.