Final answer:
Pattern recognition receptors (PRRs) are membrane-bound receptors that detect patterns of pathogen-specific molecules. They act as sensors for microbial products in the innate immune response.
Step-by-step explanation:
Pattern recognition receptors (PRRs) are membrane-bound receptors that recognize characteristic features of a pathogen and molecules released by stressed or damaged cells. They play a crucial role in the innate immune response by detecting patterns of pathogen-specific molecules. PRRs act as sensors for microbial products, allowing cells of the immune system to identify and respond to invading pathogens.