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