Antibiotic
a substance that inhibits the growth of or kills microoganisms.
Autotroph
an organism that produces its own nutrients from inorganice substances or from the enviornment instead of consuming other organisms.
Antibiotic resistance
the ability of a population of bacteria to survive the lethal effects of an antibiotic.
Bacillus
a rod-shaped bacterium.
Bioremediation
the biological treatment of hazardous waste by natural or genetically engineered microorganisms.
Coccus
a sphere-shaped bacterium.
Capsule
in mosses, the part that contains spores; in vacteria, a protective layer of polysaccharides around the cell wall.
Chemotroph
an organism that gets its energy from chemicals taken from the environment.
Conjugation
in algae and fungi, an exchange of genetic material that occurs between two temporarily joined cells; in prokaryotes, the process by which two organisms bind together and onew cell transfers DNA to the ohter cell through a structure called a sex pilus.
Endospore
a thick-walled protective spore that forms inside a bacterial cell and resists harsh conditions.
Facultative anaerobe
an organism that can live with or without oxygen.
Gram-negative bacterium
a bacterium that, in the Gram stain process, is stained reddish-pink and that has a small amount of peptidoglycan in its cell wall.
Gram-positive bacterium
a bacterium that, in the Gram stain process, is stained purple and that has a large amount of peptidoglycan in its cell wall.
Glycocalyx
a vacterial capsule that is made of a fuzzy coat of sticky sugars.
Halophile
an organism that can grow in , or favors environments that have very high salt concentration.
Obligate anaerobe
an organism that needs the absence of oxygen in order to live.
Obligate aerobe
an organism that requires oxygen to survive.
Prokaryote
a single-celled organism that has no nucleus and has no membrane-bound organelles; examples include bacateria and archae.
Peptidoglycan
a protein-carbohydrate compound that makes the cell walls of bacteria rigid.
Phototroph
an organism that gets its energy from sunlight.
Plasmid
a circular DNA molecule that is usually found in bacteria and that can replicate independent of the main chromosome.
Pilus
a short, thick hair-like protein structure that allows a bacterium to attach to other bacteria and surfaces.
Pathology
the scientific study of disease.
Methanogen
a microorganism that produces methane gas.
Spirillum
a spiral-shaped bacterium
Streptococcus
a coccus that grows with others in chaines; examples include cocci of the disease-causing species Streptococcus mutans.
Staphlyococcus
a coccus that grows with others in grapelike clusters; examples include cocci of the species Staphlococcus aureus.
Thermoacidophile
an organism that grows well in a warm, acidic environment.
Transformation
the transfer of genetic material in the form of DNA tragments from one cell to another or from one organism to another.
Transduction
the transfer of bacterial gene from one bacterium to another through a bacteriophage.
Zoonosis
a disease that can pass from animals to humans; an example is Lyme disease, which can be passed from deer to humans through infected ticks.
Exotoxin
a potent, extracellular toxin secreted by some gram positive bacteria.
Heterotroph
an organism that obtains organic food molecules by eating other organisms or their byproducts and that cannot synthesize organic compunds from inorganice materials.
Endotoxin
a toxin that occurs in the outer membrane of Gram negative bacteria and that is releasesd when the vacterial cell breaks apart.