bacteria and archaea

• network of modified sugar polymers ross linked by short polypeptides
• encloses the entire bacterium and anchors other molecules that extend from its surface

lacking in archaeal cell walls

used to classify many bacterial species into two groups based on cell wall composition

bacteria have simpler walls with large amount of peptidoglycan

less peptidoglycan and structurally more complex with an outer membrane that contains lipopolysaccharides

• sticky layer of polysaccharide or protein
• enables prokaryotes to adhere to their substrate or to other individuals in a colony

hairlike protein appendages that help prokaryotes stick to their substrate or to one another

region of cytoplasm that appears lighter than the surrounding cytoplasm

smaller rings of separately replicating DNA

• resistant cells produced when essential nutrient is lacking
• the original cell produces a copy of its chromosome and surrounds it with a tough wall

genotype and possibly phenotype of a prokaryotic cell are altered by the uptake of foreign DNA from its surroundings

• bacteriophages carry bacterial genes from one host cell to another
• a type of horizontal gene transfer

genetic material is transferred between two bacterial cells that are temporarily joined

• consists of about 25 genes
• can exist either as aplasmid or as a segment of DNA within a bacterial chromosome

resistance genes carried by plasmids

photosynthetic organisms that capture light energy and use it to drive the synthesis of organic compounds from COs or other inorganic carbon compounds

need only as inorganic compound such as CO2 as a carbon source

harness energy from light but must obtain carbon in organic form

must consume organic molecules to obtain both energy and carbon

use O2 for cellular respiration and cannot grow without it

• are poisoned by O2
• some live by fermentation

nitrate ions or sulfate ions accept electrons at the downhill end of electron transport chains

use O2 if it is present but can also carry out anaerobic environment

convert atmospheric nitrogen to ammonia

carry out only nitrogen fixation

surface-coating colonies in which metabolic cooperation between different prokaryotic species occurs

"lovers" of extreme conditions

live in highly saline environments

thrive in very hot environments

use CO2 to oxidize H2 releasing methane as a waste product

• breaking down corpses, dead vegetation and waste products
• unlocking supplies of carbon, nitrogen, and other elemnts

an ecological relationship in which two species live in close contact with one another

both benefit

one species benefits while the other is not harmed or helped in any significant way

a parasite eats the cells contents, tissues, or body fluids of its host

proteins secreted by certain bacteria and other organisms

lipopolysaccharide components of the outer membrane of gram-negative bacteria