Bacteria
single-celled organisms that do not have a nucleus; prokaryotes
Archaea
prokaryotic, single-celled organisms that live in extreme environments
Prokaryotic
An organism whose cells do not have an enclosed nucleus, such as bacteria.
Unicellular
Made of a single cell
cell membrane
A cell structure that controls which substances can enter or leave the cell.
cell wall
A rigid structure that surrounds the cell membrane and provides support to the cell
Flagellum
A long, hairlike structure that grows out of a cell and enables the cell to move.
Cytoplasm
A jellylike fluid inside the cell in which the organelles are suspended
capsule
A sticky layer that surrounds the cell walls of some bacteria, protecting the cell surface and sometimes helping to glue the cell to surfaces.
Pili
short, hairlike protein structures on the surface of some bacteria
asexual reproduction
A reproductive process that involves only one parent and produces offspring that are identical to the parent.
binary fission
A form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size
Conjugation
In bacteria, the direct transfer of DNA between two cells that are temporarily joined.
DNA
A complex molecule containing the genetic information that makes up the chromosomes.
Autotroph
An organism that makes its own food
Heterotroph
organism that obtains energy from the foods it consumes; also called a consumer
Virus
A tiny, nonliving particle that invades and then reproduces inside a living cell.
Spirilla
spiral shaped bacteria
Coccus
A spherical bacterium.
Bacillus
rod-shaped bacteria