Identify the statement that is NOT correct.
Answer: (A) Antigen binding site is located at C-terminal region of antibody molecules.. Answer: (A) Antigen binding site is located at C-terminal region of antibody molecules.
- A.Antigen binding site is located at C-terminal region of antibody molecules.✓
- B.Constant region of heavy and light chains are located at C-terminus of antibody molecules.
- C.Each antibody has two light and two heavy chains.
- D.The heavy and light chains are held together by disulfide bonds.
Correct Answer
(A) Antigen binding site is located at C-terminal region of antibody molecules.
Solution & Explanation
Answer: (A) Antigen binding site is located at C-terminal region of antibody molecules. [This is the statement that is NOT correct.] Solution: The antigen-binding site lies in the VARIABLE region, formed by the N-terminal ends of the heavy and light chains — not the C-terminal. The constant regions of the heavy and light chains lie at the C-terminus. So the statement placing the antigen-binding site at the C-terminal is incorrect and is the answer to 'identify the statement that is NOT correct'. Why the others are correct: Each antibody has two light and two heavy chains (NCERT: H2L2), and the heavy and light chains are held together by disulfide bonds (shown in Fig. 7.4), and the constant regions are indeed at the C-terminus. These are all true statements. NCERT Reference: NCERT Ch7, p.135, lines 39-44 (and Figure 7.4): "two small called light chains and"