Which of the Following is False About Exotoxins

Question

Which of the following is false about exotoxins?
A) Part of the exotoxin called the "A subunit" binds to receptors on the surface of certain host cells.
B) The combined exotoxin (both the A & B subunits) enter the host cell by endocytosis.
C) They may be produced by either Gram-positive or Gram-negative bacteria.
D) They are generally more toxic than endotoxins at low concentration.
E) They are composed of protein.

Accepted Answer

The "A subunit" of an exotoxin is actually the part that has enzymatic activity and alters host cell function, not the part that binds to receptors. The "B subunit" is responsible for binding to the host cell surface.