Answer: Recognize and bind to specific antigens on pathogens, marking them for destruction.
- A Inject toxic enzymes directly into pathogen cells to rupture their membranes
- B Recognize and bind to specific antigens on pathogens, marking them for destruction
- C Trigger localized inflammation and swelling at the site of pathogen entry
- D Digest engulfed pathogens inside the phagocyte's lysosomal compartments
Correct answer: B. Recognize and bind to specific antigens on pathogens, marking them for destruction
Explanation: Antibodies (immunoglobulins) are Y-shaped proteins produced by plasma cells (activated B cells). They bind specifically to antigens on pathogens, neutralizing them or marking them for destruction by other immune cells.
An antibody is Y-shaped, with two identical antigen-binding sites at the tips of the variable regions - each shaped to recognise one specific antigen - while the constant (Fc) region at the base is recognised by immune cells to trigger further responses.
Concept context
Innate and adaptive immunity, B cells, T cells, antibodies, vaccines, and immune disorders. Critical for NEET.