bacteria

domain archaea, kingdom archaebacteria

no peptidoglycan in cell walls, many are anaerobes

domain bacteria, kingdom eubacteria

cell walls contain peptidoglycan found almost everywhere

chemoheterotrophs

use organic chemicals as sources of energy and consumer organic carbon compounds

photoheterotrophs

use light for energy but consume organic carbon compounds

photoautotrophs

use photosynthesis to produce energy

chemoautotrophs

an organism that takes inorganic chemicals and transforms it into energy

obligate aerobes

must have oxygen

obligate anaerobes

can’t have oxygen (fermentation)

facultative anaerobes

can survive with or without oxygen

coccus

sphere shaped

bacillus

rod shaped

spirillum

spiral shaped

diplo-

pairs

staphylo-

clusters

strepto-

chains

gram positive

stained purple, thick layer of peptidoglycan in cell wall, killed by penicillin b/c of interference with cell wall

gram negative

stained pink, thin layer of peptidoglycan in cell wall; have outer membrane, resistant to penicillin b/c of outer membrane, but not tetracycline

structure of bacteria

prokaryotic, single circular chromosome (nucleoid is area where DNA is located), ribosomes, may have flagella, may have pili (hairlike structures on plasma membrane), have cell wall to protect cell from rupturing, may have capsule — outside cell wall to protect and makes it more likely to cause disease

unfavorable conditions

produce endospores (hard outer covering; can’t grow or reproduce)

favorable conditions

endospore breaks down and bacteria can now grow and reproduce

harmful bacteria can:

release harmful toxins (poisons) that inhibit protein synthesis or damage cell membranes, or destroy cells directly

antibiotics

some interfere with enzyme that makes cell wall, others interfere with metabolic activity (blocking growth and reproduction)

sterilization

kills endospores, requires high pressure and heat

vaccines

prevent disease

disinfectants

kills bacteria on surfaces

binary fission

how bacteria reproduce

conjugation

a sexual process, one bacterium transfers DNA plasmid to another cell through pili (no true sexual reproduction)

economic importance

food, medicines, genetic engineering, sewage treatment plants, control insect pests, nitrogen fixation and conversion of ammonia, form root nodules to help plants grow and enrich the soil, recycle nutrients, helpful to humans — make vitamin k, aid digestion, take up space so other pathogenic bacteria don’t have room