The 3 Domains; Prokaryotes
Saprobe
(decomposers). Degrade organic matter. Most natural organic compounds can be metabolized by some bacterium. Exceptions: human-made non-biodegradable plastics.
Flagellum
A long, hairlike structure that grows out of a cell and enables the cell to move.
Peptidoglycan
A protein-carbohydrate compound that makes the cell walls of bacteria rigid
Gram- positive bacteria
Thick peptidoglycan outside single membrane
Gram- negative bacteria
Thin peptidoglycan sandwiched between two membranes
Transformation
Uptake of DNA from outside the cell.
Transduction
Viral transfer of DNA.
Phototrophic
organisms which use light as an energy source for production of organic molecules.
Heterotrophic
An organism that cannot make its own food.
Autotrophic
An organism that makes its own food
Conjugation
Direct transfer of DNA via pili.
Eukarya
Domain of all organisms whose cells have nuclei, including protists, plants, fungi, and animals
Archaea
Domain of unicellular prokaryotes that have cell walls that do not contain peptidoglycan. - Some are extremophiles -Thermophiles: withstand extreme temp. -Halophiles: withstand extremely saline environments - dead sea, great salt lake
Chemotropic
Organisms that acquire their energy through chemical processes.
Nitrogen Fixation
Process of converting nitrogen gas into ammonia. (soil bacteria)
Bacteria
single-celled spherical or spiral or rod-shaped organisms lacking chlorophyll that reproduce by binary fission(asexual).
Bacterial Biofilm
• Adhere to surfaces with a polysaccharide matrix. • Often multiple species, metabolically cooperating.
The Three Domain System
• Bacteria and Archaea are both prokaryotes but differ enough to be placed in separate domains. • An ancestor of modern Archaea is believed to have given rise to Eukarya, the third domain of life. These are from the kingdom Animalia
Bacterial Capsule
• Sticky polysaccharide secretion for protection, adhesion.
Prokaryotes
• oldest detectable fossil • ubiquitous(everywhere), widely adapted • small, usually unicellular • variety of shapes • Can be parasites, pathogens: absorb nutrients from live host cells
