Post on 23-Feb-2016
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Chapter 18.2
Archaebacteria and Eubacteria
Organisms in these two kingdoms are prokaryotes have no membrane bound organelles
Kingdom Archaebacteria (extremophiles)Usually live where there is no oxygen
(anaerobic)3 types
Methane-producing live in swamps and cows stomachs
Salt-loving live in lakes with a high mineral content
Acid and Heat-loving live around deep ocean vents with temps above 100 OC
Kingdom Eubacteria (true bacteria)Heterotrophic use organic molecules as a food
sourceSome are parasites obtaining nutrition from living
organismsSome are saprophytes obtaining nutrition from dead
organisms and organic waste (poop)Photosynthetic autotroph cyanobacteria
Produce chemical energy through photosynthesisChemosynthetic autotroph
Break down and release energy from compounds containing sulfur or nitrogen
Called chemosynthesis
General Structure of a BacteriumContain very small ribosomesSingle circular chromosomeCell wall prevents bacteria from
burstingCapsule a sticky gelatinous layer
outside of the cell wallFlagellum a whip-like projection
that help the bacterium movePilus air-like structures coming out
the cell surface, help bacteria stick to surfaces
Plasmid a few genes in a circular chromosome
Life of a BacteriumMost bacteria live in an environment
where there is more water outside than inside so water is always trying to get inAs long as the cell wall is intact, bacteria will
still surviveAntibiotics and plain old soap cause holes to
develop in the cell wall causing the bacteria to burst (die)
Identifying bacteriaGram stain shows
differences in cell wall structureGram positive stain purpleGram negative stain pink
ShapeCocci sphereBacillus rodSpirilli spiral
Growth patternsDiplo pairsStaphylo grape-like clustersStrepto long chain
ReproductionBinary fission a form of asexual
reproduction that produces identical offspring Some bacteria can reproduce every 20
minutes in ideal conditionsConjugation a form of sexual
reproduction where on bacteria transfers it chromosome to another through a pilus Creates genetic diversity
Bacterial diversityMetabolism
Obligate aerobes require oxygen to respire Obligate anaerobes die in the presence of
oxygenSurvival
Some bacteria form a tough outer layer called an endospore that allows them to survive when water is scarce
How are bacteria helpful and harmful?
Some bacteria fix nitrogen into a form that plants can use
Recycle nutrientsUsed to make food and
medicineCheese, yogurt, some antibiotics
Can cause diseaseAnthrax, tuberculosis, cavities,
strep throat