AP BIOLOGY

Detailed explanation-1: -Macrophages are the body’s first line of defense and have many roles. A macrophage is the first cell to recognize and engulf foreign substances (antigens).

Detailed explanation-2: -A macrophage is a large, phagocytic cell that engulfs foreign particles and pathogens. Macrophages recognize PAMPs via complementary pattern recognition receptors (PRRs). PRRs are molecules on macrophages and dendritic cells which are in contact with the external environment and can thus recognize PAMPs when present.

Detailed explanation-3: -Infecting bacteria are usually coated with complement and antibodies once they enter the tissues, and this allows neutrophils to easily recognize the bacteria as something foreign. Neutrophils then engulf the bacteria and destroy them (Figure 1:4).

Detailed explanation-4: -Macrophages detect pathogenic microorganisms by expressing pattern recognition receptors (PRRs), which interact with conserved microbe-associated molecular patterns (MAMPs).