Q43-4TYU.
Question
Which of the following statements is not true?
(A) An antibody has more than one antigen-binding site.
(B) A lymphocyte has receptors for multiple different antigens.
(C) An antigen can have different epitopes.
(D) A liver or muscle cell makes one class of MHC molecule.
Step-by-Step Solution
Verified(A) The statement “an antibody has more than one antigen-binding site” is false.
(B) The statement “a lymphocyte has receptors for multiple different antigens” is true.
(C) The statement “an antigen can have different epitopes” is false.
(D) The statement “A liver or muscle cell makes one class of MHC molecule” is false.
The cells present in jawed animals produced from the bone marrow to protect the body from pathogens are lymphocytes. They are present in blood and lymph. T and B cells are two categories of lymphocytes. The coordination between these cells kills the antigen and infected cells.
There are two antigen-binding sites present on the antibodies. The two identical chains are light and heavy.
Therefore, two antigen-binding sites are present on a single antibody.
Thus, the given statement is false.
A single antigenic determinant is capable of binding to a lymphocyte. A single lymphocyte recognizes one specific antigen.
Therefore, a lymphocyte does not consist of receptors for multiple antigens.
Thus, the given statement is true.
Antigens comprise at least a single epitope. When an antigen has more than one epitope, it is called cross-reacting antigens.
Therefore, antigens can have more than one epitope.
Thus, the given statement is false.
The hepatocytes of the liver are capable of expressing MHC class I. They do not express MHC II. However, during rare occasions, MHC II is expressed during the inflammation. The muscles cells do not express MHC I molecules.
Therefore, the liver and muscle cells are capable of expressing only one set of MHC molecules.
Thus, the given statement is false.