Viruses, Bacteria and the Immune System Vocabulary

pathogen any organism that causes disease

virus Pathogen that needs a host cell in order to survive

bacteria eubacteria archaebacteria single-celled (unicellular) that can cause disease eubacteria archaebacteria True bacteria Found in soil and in intestines in animals Have cell walls and flagella Similar in shape and size to eubacteria VERY different from eubacteria Found in EXTREME environments Thermophiles (temp) Hot mud/geysers/arctic Halophiles (salty) Dead Sea Methanogens (methane) swamps

bacteriophage virus that infects bacteria

toxin any poison produced by an organism

parasite an organism that lives on/in or near a host and causes harm to it

host where parasites obtains what it needs

Infectious disease A disease caused by a microorganism that enters the body

antibiotic man- made chemical that destroys pathogens

AIDS (Acquired Immunodeficiency Syndrome) – A disease of the immune system caused by a virus

vaccine used to help prevent a specific disease. Usually contains a small amount of the dead or weakened virus or bacteria

homeostasis ability of an organism to maintain a stable internal environment

barriers Obstructs (blocks) something from entering.

Inflammatory response Fluid and white blood cells leak from blood vessels into the area

Immune response Cells react to each kind of pathogen to fight

antigen molecule coming from outside the body that is capable of causing a response

antibodies substances produced in human body, marks to destroy specific antigens