Final answer:
Yes, both Immunoglobulins (Igs) and T Cell Receptors (TCRs) have Hypervariable Complementarity Determining Regions within their variable domains, which are key to the immune system's ability to recognize a vast array of antigens through genetic rearrangements that produce diversity.
Step-by-step explanation:
Both Immunoglobulins (Igs) and T Cell Receptors (TCRs) possess Hypervariable Complementarity Determining Regions within their variable domains. Ig's like the heavy chains, contain hypervariable regions (CDRs) amid more conserved framework regions. These CDRs, comprising about 15-20% of the variable domain, interact with light chains to form antigen-binding sites. On the other hand, TCRs feature a pair of chains, each with a variable and a constant domain. The antigen-binding site is at the terminal ends of TCR chains, where amino acid sequence diversity enables the recognition of different antigens, underpinning the immune system's ability to respond to countless possible antigens. This diversity is a result of genetic rearrangements in precursor cells, forming millions of unique binding sites.