A tiny, nonliving particle that invades and then reproduces inside a living cell.
An organism that a parasite or virus lives in or on.
The organism that benefits by living on or in a host in a parasitism interaction
A virus that infects bacteria.
A substance used in a vaccination that consists of weakened or killed pathogens that can trigger the immune system into action
Single-celled organisms that lack a nucleus; prokaryotes.
A long, whiplike structure that helps a cell to move.
A form of asexual reproduction in which one cell divides to form two identical cells.
A reproductive process that involves only one parent and produces offspring that are identical to the parent.
A reproductive process that involves two parents that combine their genetic material to produce a new organism, which differs from both parents.
The process in which a unicellular organism transfers some of its genetic material to another unicellular organism.
A small, rounded, thick-walled, resting cell that forms inside a bacterial cell.
A process of heating food to a temperature that is high enough to kill most harmful bacteria without changing the taste of the food.
An organism that breaks down chemicals from dead organisms and returns important materials to the soil and water.
A eukaryotic organism that cannot be classified as an animal, plant, or fungus.
An animal-like protist.
A "false foot" or temporary bulge of cytoplasm used for feeding and movement in some protozoans.
The cell structure that collects extra water from the cytoplasm and then expels it from the cell.
The hairlike projections on the outside of cells that move in a wavelike manner.
A close relationship between two organisms in which at least one of the organisms benefits.
A type of symbiosis in which both partners benefit from living together.
A tiny cell that is able to grow into a new organism.
A eukaryotic organism that has cell walls, uses spores to reproduce, and is a heterotroph that feeds by absorbing its food.
The branching, threadlike tubes that make up the bodies of multicellular fungi.
The reproductive structure of a fungus that contains many hyphae and produces spores.
A form of asexual reproduction of yeast in which a new cell grows out of the body of a parent.
The combination of a fungus and either an alga or an autotrophic bacterium that live together in a mutualistic relationship.