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BacteriaBacteria

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Structure and FunctionStructure and Function

Prokaryote & Prokaryote & EukaryoteEukaryote

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EukaryoteEukaryoteEvolutionEvolution

Cellular EvolutionCellular Evolution•• Current evidence Current evidence indicates that indicates that eukaryotes eukaryotes evolved from prokaryotesevolved from prokaryotes

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f p yf p ybetween 1 and 1.5 billion between 1 and 1.5 billion years agoyears ago

•• Two theories:Two theories:1.1. Infolding theoryInfolding theory2.2. Endosymbiotic theoryEndosymbiotic theory

Infolding TheoryInfolding Theory•• The The infolding of the infolding of the prokaryotic plasmaprokaryotic plasmamembrane gave rise to membrane gave rise to

k ti llk ti ll

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eukaryotic organelles.eukaryotic organelles.

infolding organelle

Endosymbiotic TheoryEndosymbiotic Theory•• Endosymbiosis refers to Endosymbiosis refers to one one

species living within anotherspecies living within another(the (the host)host)

•• Movement of Movement of smaller smaller photosyntheticphotosynthetic & & heterotrophicheterotrophic

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p yp y ppprokaryotesprokaryotes into larger into larger prokaryotic host cellsprokaryotic host cells

•• Formed Formed cell organellescell organelles chloroplast

mitochondria

Prokaryotic & Prokaryotic & Eukaryotic CellsEukaryotic Cells

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Earliest Earliest ProkaryotesProkaryotes•• Most numerousMost numerousorganisms on Earth

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• Include allbacteriabacteria

•• Earliest fossils Earliest fossils datedate 2.5 billion years old

Classification Classification of Lifeof Life

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of Lifeof Life

Three Domains of Three Domains of LifeLife

•• ArchaeaArchaea ––prokaryotes living in prokaryotes living in extreme habitatsextreme habitats

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•• BacteriaBacteria--Cyanobacteria and Cyanobacteria and eubacteriaeubacteria

•• EukaryaEukarya ––Protozoans, fungi, Protozoans, fungi, plants, & animalsplants, & animals

Kingdoms of BacteriaKingdoms of Bacteria

Archaebacteria:Archaebacteria:Found in Found in harsh harsh n i nm ntn i nm nt

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environmentsenvironmentsUndersea Undersea volcanic ventsvolcanic vents, , acidic acidic hot springshot springs, , saltysaltywaterwater

ArchaebacteriaArchaebacteria

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Kingdoms of BacteriaKingdoms of BacteriaEubacteria:Eubacteria:

Called the Called the true true bacteriabacteria

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bacteriabacteriaMost bacteriaMost bacteria are in are in this groupthis groupInclude photosynthetic Include photosynthetic CyanobacteriaCyanobacteria

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EubacteriaEubacteria

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Characteristics Characteristics of Bacteriaof Bacteria

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of Bacteriaof Bacteria

Bacterial StructureBacterial Structure•• Microscopic Microscopic prokaryotesprokaryotes•• No No nucleus or membranenucleus or membrane--bound organellesbound organelles

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•• Contain Contain ribosomesribosomes•• Single, circular Single, circular chromosome in chromosome in nucleoid nucleoid regionregion

Bacterial Cell

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ProtectionProtection•• Cell Wall made of Cell Wall made of PeptidoglycanPeptidoglycanMay have a sticky May have a sticky

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•• May have a sticky May have a sticky coating called the coating called the Capsule Capsule for for attachment to host or attachment to host or other bacteriaother bacteria

Sticky Bacterial Sticky Bacterial CapsuleCapsule

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Bacterial Bacterial StructureStructure

•• Have small rings of Have small rings of DNA called DNA called PlasmidsPlasmids

PLASMIDSPLASMIDS

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DNA called DNA called PlasmidsPlasmids•• UnicellularUnicellular•• SmallSmall in size (0.5 to in size (0.5 to 2μm)2μm)

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Bacterial StructureBacterial Structure

•• Most grow best at Most grow best at pH of 6.5 to 7.0pH of 6.5 to 7.0M t M t

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•• Many act as Many act as decomposersdecomposers recycling recycling nutrientsnutrients

•• Some cause Some cause diseasedisease

Staphylococcus Staphylococcus BacterialBacterial

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Useful BacteriaUseful Bacteria

•• Some Some bacteria bacteria can can

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can can degrade oildegrade oil

•• Used to Used to clean up clean up oil oil spillsspills

Useful BacteriaUseful Bacteria•• Other uses Other uses for bacteria for bacteria include include

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include include making making yogurt, yogurt, cheese, and cheese, and buttermilk.buttermilk.

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FlagellaFlagella•• Bacteria that Bacteria that are are motile motile have have appendages appendages called called flagellaflagella

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•• Attached byAttached byBasal BodyBasal Body

•• A bacteria can A bacteria can have have one or one or manymany flagellaflagella

PiliPili•• Short proteinShort protein appendagesappendages•• SmallerSmaller than flagellathan flagella•• AdhereAdhere bacteria to bacteria to surfacessurfaces

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surfacessurfaces•• Used in Used in conjugationconjugation for for Exchange of genetic Exchange of genetic informationinformation

•• AidAid Flotation Flotation by by increasing buoyancyincreasing buoyancy

Pili in ConjugationPili in Conjugation

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Bacterial Bacterial

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ShapesShapes

Shapes Are Used to Shapes Are Used to ClassifyClassify

•• Bacillus: Bacillus: Rod shapedRod shaped•• Coccus: Coccus: Spherical (round)Spherical (round)

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•• Vibrio: Vibrio: Comma shaped with Comma shaped with flagellaflagella

•• Spirillum: Spirillum: Spiral shapeSpiral shape•• Spirochete: Spirochete: wormlike wormlike spiral shapespiral shape 30

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Grouping of BacteriaGrouping of Bacteria

•• DiploDiplo-- Groups of Groups of twotwo

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•• StreptoStrepto-- chainschains•• StaphyloStaphylo-- Grapelike Grapelike clustersclusters

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DiplococcusDiplococcus

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Streptococcus Causes Streptococcus Causes Strep ThroatStrep Throat

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StaphylococcusStaphylococcus

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Bacillus Bacillus -- E. coliE. coli

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StreptobacilliStreptobacilli

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SpirillumSpirillum

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SpirochetesSpirochetes

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LeptospiraLeptospira

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Bacterial Bacterial KingdomsKingdoms

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ArchaebacteriaArchaebacteria

•• Lack peptidoglycanLack peptidoglycan in cell in cell wallswalls

•• Have Have different lipidsdifferent lipids in in h ll bh ll b

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their cell membranetheir cell membrane•• Different types of Different types of ribosomesribosomes

•• Very Very different genedifferent genesequencessequences

ArchaebacteriaArchaebacteria•• Archaebacteria can live in Archaebacteria can live in extremely harsh extremely harsh environmentsenvironments

•• They They do not require oxygendo not require oxygen

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•• They They do not require oxygendo not require oxygenand can live in and can live in extremely extremely saltysalty environments as well as environments as well as extremely hotextremely hot environmentsenvironments

•• Called the Called the Ancient bacteriaAncient bacteria

ArchaebacteriaArchaebacteria

•• Subdivided into 3 Subdivided into 3 groups:groups:

hh

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MethanogensMethanogensThermoacidophilesThermoacidophilesExtreme HalophilesExtreme Halophiles

MethanogensMethanogens•• Live in Live in anaerobic anaerobic environments (no oxygen)environments (no oxygen)

•• Get energy by Get energy by changing Hchanging H22

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Get energy by Get energy by changing Hchanging H22& CO& CO22 into methane gasinto methane gas

•• Found in Found in swampsswamps, , sewage sewage treatmenttreatment plants, plants, digestive digestive tractstracts of animalsof animals

MethanogensMethanogens•• Break down Break down cellulose in a cellulose in a cow’scow’s

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stomachstomach•• Produce Produce marsh marsh (methane) (methane) gasgas

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Extreme HalophilesExtreme Halophiles•• Live in very Live in very salty watersalty water

•• Use Use salt to salt to

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generate generate ATPATP (energy)(energy)

•• Dead Sea, Dead Sea, Great Salt Great Salt LakeLakeinhabitantsinhabitants

Thermoacidophiles or Thermoacidophiles or ThermophilesThermophiles

•• Live in Live in extremely hot extremely hot environmentsenvironments

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•• Found in Found in volcanicvolcanic vents, vents, hot springs, hot springs, cracks on ocean cracks on ocean floor that leak floor that leak acidacid

Kingdom Kingdom EubacteriaEubacteria

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True BacteriaTrue Bacteria

CharacteristicsCharacteristics•• 3 basic shapes3 basic shapes (coccus, (coccus, bacillus, spirilla)bacillus, spirilla)

•• Most are Most are heterotrophic heterotrophic

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Most are Most are heterotrophic heterotrophic (can’t make their own food)(can’t make their own food)

•• May be May be aerobic or aerobic or anaerobicanaerobic

•• Identified by Identified by Gram stainingGram staining

Gram StainingGram Staining•• Developed in Developed in 1884 by 1884 by Hans GramHans Gram

•• Bacteria treated with Bacteria treated with

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Bacteria treated with Bacteria treated with purple Crystal Violet & red purple Crystal Violet & red Safranin stainsSafranin stains

•• Cell wallsCell walls either stain either stain purple or reddish pinkpurple or reddish pink

Gram PositiveGram Positive•• Have Have thick layer thick layer of peptidoglycanof peptidoglycan(protein(protein--sugar sugar

l )l )

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complex)complex)•• Single lipid Single lipid layerlayer

•• Stain Stain purplepurple•• Can be treated Can be treated with with antibioticsantibiotics

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Gram Positive Gram Positive BacteriaBacteria

Lactobacilli Lactobacilli (makes yogurt & (makes yogurt & buttermilk)buttermilk)Actinomycetes (Actinomycetes (make make

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yyantibiotics)antibiotics)Clostridium Clostridium (lockjaw bacteria)(lockjaw bacteria)Streptococcus Streptococcus (strep throat)(strep throat)Staphylococcus (Staphylococcus (staph staph infections)infections)

Gram Negative Gram Negative BacteriaBacteria

•• Thin layer of peptidoglycanThin layer of peptidoglycan in in cell wallcell wall

•• Extra Extra thick layer of lipidsthick layer of lipids

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y py p•• Stain Stain pink or reddishpink or reddish•• Hard to treatHard to treat with antibioticswith antibiotics•• Some Some photosyntheticphotosynthetic but but make sulfur not oxygenmake sulfur not oxygen

•• Some Some fix nitrogenfix nitrogen for plantsfor plants

Gram NegativeGram Negative•• Rhizobacteria Rhizobacteria

grow in root grow in root nodules of nodules of ll

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legumeslegumes(soybeans, (soybeans, peanuts)peanuts)

•• Fix NFix N22 from air from air into usable into usable ammoniaammonia

Gram NegativeGram Negative•• Rickettsiae Rickettsiae are are parasitic parasitic bacteria bacteria

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carried by tickscarried by ticks•• Cause Cause Lyme Lyme disease & Rocky disease & Rocky Mountain Mountain Spotted FeverSpotted Fever

CyanobacteriaCyanobacteria

•• Gram Gram negativenegative•• PhotosyntheticPhotosynthetic

ll d ll d blbl b b

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•• Called Called blueblue--green bacteriagreen bacteria•• Contain Contain phycocyaninphycocyanin (red(red--blue) pigments & blue) pigments & chlorophyllchlorophyll

CyanobacteriaCyanobacteria•• May be red, yellow, brown, black, May be red, yellow, brown, black,

or blueor blue--greengreen•• May grow in May grow in chainschains ((OscillatoriaOscillatoria))

H H H t tH t t t h l fi Nt h l fi N

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•• Have Have HeterocystsHeterocysts to help fix Nto help fix N22•• First to reFirst to re--enterenter devastated devastated

areasareas•• Some cause Some cause EutrophicationEutrophication (use up (use up

O2 when die & decompose in O2 when die & decompose in water)water)

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CyanobacteriaCyanobacteria

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Nutrition, Nutrition, Respiration, Respiration,

and and

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and and ReproductionReproduction

Modes of NutritionModes of Nutrition•• Saprobes Saprobes –– feed on dead feed on dead organic matterorganic matter

•• ParasitesParasites –– feed on a host feed on a host cellcell

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cellcell•• PhotoautotrophPhotoautotroph –– use use sunlight to make foodsunlight to make food

•• ChemoautotrophChemoautotroph –– oxidize oxidize inorganic matter such as inorganic matter such as iron or sulfur to make foodiron or sulfur to make food

Methods of RespirationMethods of Respiration

•• Obligate AerobesObligate Aerobes –– require require OO22 (tuberculosis bacteria)(tuberculosis bacteria)

•• Obligate AnaerobesObligate Anaerobes –– die if die if

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Obligate AnaerobesObligate Anaerobes die if die if OO22 is present (tetanus)is present (tetanus)

•• Facultative AnaerobesFacultative Anaerobes –– don’t don’t need Oneed O22, but aren’t killed by , but aren’t killed by it (it (E. coliE. coli))

Bacterial RespirationBacterial Respiration•• AnaerobesAnaerobescarry on carry on fermentationfermentation

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•• Aerobes Aerobes carry on carry on cellular cellular respirationrespiration

ReproductionReproduction

•• Bacteria reproduce Bacteria reproduce asexually by binary fissionasexually by binary fissionSin l h m m Sin l h m m

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•• Single chromosome Single chromosome replicatesreplicates & then cell & then cell dividesdivides

•• RapidRapid•• All new cells All new cells identical identical (clones)(clones)

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Cellular organism copies it’s genetic information Cellular organism copies it’s genetic information then splits into two identical daughter cellsthen splits into two identical daughter cells

Binary Fission Binary Fission E. coliE. coli

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ReproductionReproduction

•• Bacteria reproduce Bacteria reproduce sexually by Conjugationsexually by ConjugationF m F m t b b t n 2 t b b t n 2

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•• Form aForm a tube between 2 tube between 2 bacteria bacteria to exchangeto exchangegenetic materialgenetic material

•• Held together byHeld together by pilipili•• New cellsNew cells NOT identicalNOT identical

ConjugationConjugation

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Spore FormationSpore Formation•• Form Form endosporeendospore

whenever when whenever when habitat conditions habitat conditions become become harsh harsh (littl f d)(littl f d)

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(little food)(little food)•• Able to Able to survive for survive for

long periods of long periods of timetime as endospermas endosperm

•• Difficult to Difficult to destroy (heat destroy (heat resistant)resistant)

Transduction & Transduction & TransformationTransformation

•• Genetically changeGenetically change bacteriabacteria•• May become May become antibiotic resistantantibiotic resistant•• Transformed bacteriaTransformed bacteria pick up pick up

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p pp ppieces of DNA from dead pieces of DNA from dead bacterial cellsbacterial cells

•• TransductionTransduction –– viruses carry viruses carry foreign DNA to bacteria; foreign DNA to bacteria; used used to make insulinto make insulin

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Pathenogenic Pathenogenic BacteriaBacteria

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PathogensPathogens•• Called Called germs or microbesgerms or microbes•• Cause Cause diseasedisease•• May produce May produce poisons or poisons or

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May produce May produce poisons or poisons or toxinstoxins

•• EndotoxinsEndotoxins released after released after bacteria die (bacteria die (E. coliE. coli))

•• Exotoxins Exotoxins released by Gram released by Gram + bacteria (+ bacteria (C. tetaniC. tetani))