Final answer:
PAMPs are crucial danger signals in infection. They are expressed by viruses, bacteria, and parasites and differ from molecules on host cells. When detected by PRRs on immune cells, they trigger the immune response by activating the release of cytokines.
Step-by-step explanation:
PAMPs (pathogen-associated molecular patterns) are crucial danger signals in infection. They are carbohydrate, polypeptide, and nucleic acid 'signatures' expressed by viruses, bacteria, and parasites, which differ from molecules on host cells. When these PAMPs are detected by pattern recognition receptors (PRRs) on immune cells like macrophages and dendritic cells, they trigger the immune response by activating the release of cytokines, chemical messengers that signal the presence of pathogens and the need for their destruction.