Bacteria

Unit 6: Microbiology Terms Bacteria __Prokaryotes__: Single-celled living organisms usually between 1 and 500 micrometers long. They are some of the oldest organism on the planet, and are usually called bacteria. Many kinds of prokaryotes or bacteria can cause disease.

__Eubacteria__: The larger of the two prokaryote families that include bacteria. They are made up of a cell wall, membrane, and cytoplasm. Eubacteria also have nuclei.

__Archaebacteria__: The smaller of the prokaryotes, archaebacteria have no nucleus and resemble eukaryotes more than prokaryotes. Methane producing archaebacterium are called methanogens, and they live in oxygen-free environments.

__Bacilli__: Rod-shaped prokaryotes (bacteria).

__Cocci__: Spherical-shaped prokaryotic bacteria.

__Spirilla__: Spiral or corkscrew-shaped bacteria.

__Chemoheterotrophs__: A subgroup of heterotrophs that receive their energy and nutrients from organic molecules. Many prokaryotes/bacteria are chemoheterotrophs. __Photoheterotrophs__: heterotrophic bacterium which use sunlight as an energy source (photosensitivity).

__Photoautotrophs__: autotrophic bacterium/prokaryotes which convert use light energy to convert carbon dioxide into oxygen.

__Chemoautotrophs__: autotrophic bacterium/prokaryotes which produce carbon molecules from carbon dioxide. They do not require light as a source.

__Obligate Aerobes__: Organisms, including bacteria, which require oxygen in order to live.

__Obligate Anaerobes__: Bacterium which does not require oxygen in order to live.

__Facultative Anaerobes__: bacterium that can survive either with or without oxygen.

__Binary Fission__: The process of prokaryotic reproduction that involves a bacterium doubling in size, replicating its DNA and dividing in half.

__Conjugation__: The process in which two bacteria cells exchange genetic information by forming a bridge-like structure.

__Endospore__: a type of spore formed by bacteria which allows the bacterium to survive in harsh conditions. Endospores are made of a thick internal wall that houses DNA.

__Nitrogen Fixation__: The process in which bacterium convert nitrogen gas into a form that plants can use.

Bacterial and Viral Disease

__Pathogen__: A disease causing agent; both viruses and bacteria can be pathogens.

__Vaccines__: A preparation of weakened or killed pathogens that can be used to produce immunity to certain diseases.

__Bacterial Disease__: Produced either by bacterial damaging of cells and tissues, or by releasing toxins into the body.

__Antibiotics__: Compounds that block the growth or cure bacterial disease.

__Viral Disease__: Caused by destruction of certain cells in the body.

__Viroid__: Single-stranded molecules with no surrounding protein capsid. Many are disease-causing.b

__Prions__: Protein-containing particles with no DNA or RNA. They can also cause disease.

__Sterilization__: The process of destroying pathogens by using heat.

__Disinfectants__: Chemical solutions that kill pathogens.