Q.In agglutination and precipitation reactions, the antigen is a ______________ and ____________ respectively (A) Whole cell/soluble molecule (B) Soluble molecule/whole cell (C) Bacterium/virus (D) Protein/Antibody

Antigen-antibody binding is the molecular basis of humoral immunity and proceeds in three stages: complex formation, a visible reaction (precipitation or agglutination), and finally destruction or neutralisation of the antigen. Binding strength (antibody affinity) depends on how closely antigen and antibody fit, the sum of non-covalent forces holding them (hydrogen bonds, electrostatic forces, Van der Waals forces, hydrophobic interactions), and the antibody's intrinsic affinity. The physical form of the antigen determines the visible outcome: soluble antigens produce precipitation (via precipitins), particulate antigens produce agglutination (via ag …