Question

practice mini frq

1. when a pathogen, such as a bacterium, invades the human body, the immune system is alerted. once alerted, white blood cells such as macrophages locate the pathogen and engulf it through phagocytosis. (a) describe the process of phagocytosis. (b) identify the most likely component of the plasma membrane that the immune system uses to recognize the pathogen.

Explanation:

(a) Phagocytosis is a process where phagocytes (like macrophages) extend pseudopods to surround and engulf the pathogen, forming a phagosome. The phagosome then fuses with a lysosome, and digestive enzymes break down the pathogen.
(b) The immune - system uses receptors on the plasma membrane, such as pattern - recognition receptors (PRRs), to recognize pathogen - associated molecular patterns (PAMPs) on the pathogen.

Answer:

(a) Phagocytes extend pseudopods to surround and engulf the pathogen, forming a phagosome which fuses with a lysosome for digestion.
(b) Pattern - recognition receptors (PRRs)