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