Anatomy and Physiology II (APII) Exam 3 Practice Test

Two bactericidal molecules found in sweat are lysozyme and antibodies. Lysozyme is an enzyme that attacks bacterial cell walls by cleaving the bonds in peptidoglycan, causing lysis, especially effective against Gram-positive bacteria. Antibodies present in sweat, particularly secretory IgA, bind surface antigens on bacteria, helping to prevent attachment, neutralize pathogens, and promote phagocytosis or complement actions when needed. This combination provides a frontline chemical and immune defense at the skin surface. Other options include components more associated with systemic immunity or inflammation rather than direct bactericidal activity in sweat.