Written by the Fiveable Content Team โข Last updated August 2025
Verified for the 2026 exam
Verified for the 2026 examโขWritten by the Fiveable Content Team โข Last updated August 2025
Definition
Viruses are microscopic infectious agents made up of genetic material (DNA or RNA) surrounded by a protein coat. They cannot reproduce on their own but instead infect host cells to replicate.
Pathogens include both viruses and bacteria that cause diseases in living organisms.
Immune System: The immune system is the body's defense mechanism against pathogens. It recognizes foreign substances like viruses and mounts an immune response to eliminate them.
Vaccines: Vaccines contain weakened or inactive forms of a virus (or other pathogen) that stimulate an immune response without causing illness. They help prevent future infections by training the immune system to recognize specific pathogens.