Chapter 20 - Bacteria Lecture PPT

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BacteriaBacteria

Structure and Structure and FunctionFunction

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Prokaryote Prokaryote & &

EukaryoteEukaryote

EvolutionEvolution

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Cellular EvolutionCellular Evolution

• Current evidence Current evidence indicates that indicates that eukaryotes evolved from eukaryotes evolved from prokaryotesprokaryotes between 1 between 1 and 1.5 billion years agoand 1.5 billion years ago

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

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Infolding TheoryInfolding Theory

• The The infolding of the infolding of the prokaryotic plasmaprokaryotic plasma membrane gave rise to membrane gave rise to eukaryotic organelles.eukaryotic organelles.

infolding

organelle

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Endosymbiotic Endosymbiotic TheoryTheory

• Endosymbiosis refers to Endosymbiosis refers to one species one species living within anotherliving within another(the host)(the host)

• Movement of Movement of smaller photosyntheticsmaller photosynthetic & & heterotrophicheterotrophic prokaryotesprokaryotes into into larger prokaryotic host cellslarger prokaryotic host cells

• Formed Formed cell organellescell organelles

chloroplast

mitochondria

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Prokaryotic & Prokaryotic & Eukaryotic CellsEukaryotic Cells

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Earliest Earliest ProkaryotesProkaryotes

• Most numerousMost numerous organisms on Earth

• Include all bacteriabacteria

• Earliest fossils Earliest fossils datedate 2.5 billion years old

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ClassificatioClassification of Lifen of Life

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Three Domains of Three Domains of LifeLife

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

• BacteriaBacteria- - Cyanobacteria and Cyanobacteria and eubacteriaeubacteria

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

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Kingdoms of Kingdoms of BacteriaBacteria

Archaebacteria:Archaebacteria: Found in Found in harsh harsh

environmentsenvironments Undersea Undersea volcanic volcanic

ventsvents, acidic , acidic hot hot springssprings, , saltysalty water water

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ArchaebacteriaArchaebacteria

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Kingdoms of Kingdoms of BacteriaBacteria

Eubacteria:Eubacteria: Called the Called the true true

bacteriabacteria Most bacteriaMost bacteria are in are in

this groupthis group Include Include

photosynthetic photosynthetic CyanobacteriaCyanobacteria

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EubacteriaEubacteria

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CharacteristiCharacteristics of cs of

BacteriaBacteria

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Bacterial Bacterial StructureStructure

• Microscopic Microscopic prokaryotesprokaryotes

• No No nucleus or nucleus or membrane-bound membrane-bound organellesorganelles

• Contain Contain ribosomesribosomes• Single, circular Single, circular

chromosome in chromosome in nucleoid nucleoid regionregion

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Bacterial Cell

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ProtectionProtection

•Cell Wall made of Cell Wall made of PeptidoglycanPeptidoglycan

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

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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

•UnicellularUnicellular•SmallSmall in size (0.5 to in size (0.5 to

2μm)2μm)

PLASMIDSPLASMIDS

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Bacterial Bacterial StructureStructure

•Infoldings Infoldings of cell of cell membrane carry onmembrane carry on photosynthesis & photosynthesis & cellular respirationcellular respiration

•Infoldings called Infoldings called MesosomesMesosomes

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MesosomesMesosomesMESOSOME

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Bacterial Bacterial StructureStructure

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

•Many act as Many act as decomposersdecomposers recycling nutrientsrecycling nutrients

•Some cause Some cause diseasedisease

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Staphylococcus Staphylococcus BacterialBacterial

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Useful BacteriaUseful Bacteria

• Some Some bacteria bacteria can can degrade degrade oiloil

• Used to Used to clean up clean up oil spillsoil spills

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Useful BacteriaUseful Bacteria

•Other uses Other uses for bacteria for bacteria 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

• Attached byAttached by Basal BodyBasal Body

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

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FlagellaFlagella• Made of Made of FlagellinFlagellin• Used for Used for ClassificationClassification• Monotrichous:Monotrichous: 1 flagella 1 flagella• Lophotrichous:Lophotrichous: tuft at tuft at

one endone end• Amphitrichous:Amphitrichous: tuft at tuft at

both endsboth ends• Peritrichous:Peritrichous: all around all around

bacteriabacteria

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Monotrichous Lophotrichous

Amphitrichous Peritrichous

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Question:Question:

What is this type of What is this type of bacteria ?bacteria ?

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PiliPili• Short proteinShort protein

appendagesappendages• SmallerSmaller than flagella than flagella• AdhereAdhere bacteria to bacteria to

surfacessurfaces• Used in Used in conjugationconjugation for for

Exchange of genetic Exchange of genetic informationinformation

• AidAid Flotation Flotation by by increasing buoyancyincreasing buoyancy

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Pili in ConjugationPili in Conjugation

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Bacterial Bacterial ShapesShapes

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Shapes Are Used Shapes Are Used to Classifyto Classify

• Bacillus: Bacillus: Rod shapedRod shaped

• Coccus: Coccus: Spherical (round)Spherical (round)

• Vibrio: Vibrio: Comma shaped Comma shaped with flagellawith flagella

• Spirillum: Spirillum: Spiral shapeSpiral shape

• Spirochete: Spirochete: wormlike wormlike spiral shapespiral shape

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Grouping of Grouping of BacteriaBacteria

•DiploDiplo- Groups of - Groups of twotwo

•StreptoStrepto- chains- chains•StaphyloStaphylo- -

Grapelike Grapelike clustersclusters

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DiplococcusDiplococcus

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Streptococcus Streptococcus Causes Strep ThroatCauses Strep Throat

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StaphylococcusStaphylococcus

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Bacillus - Bacillus - E. E. colicoli

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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 in cell wallscell walls

• Have Have different lipidsdifferent lipids in their cell in their cell membranemembrane

• Different types of Different types of ribosomesribosomes

• Very Very different genedifferent gene sequencessequences

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ArchaebacteriaArchaebacteria

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

• They They do not require do not require oxygenoxygen and can live in and can live in extremely saltyextremely salty environments as well as environments as well as extremely hotextremely hot environmentsenvironments

• Called the Called the Ancient bacteriaAncient bacteria

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ArchaebacteriaArchaebacteria

•Subdivided into Subdivided into 3 groups:3 groups:

MethanogensMethanogensThermoacidophilThermoacidophil

esesExtreme Extreme

HalophilesHalophiles

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MethanogensMethanogens

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

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

• Found in Found in swampsswamps, , sewage sewage treatmenttreatment plants, plants, digestive tractsdigestive tracts of animals of animals

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MethanogensMethanogens

• Break down Break down cellulose in cellulose in a cow’sa cow’s stomachstomach

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

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Extreme Extreme HalophilesHalophiles

• Live in very Live in very salty watersalty water

• Use Use salt to salt to generate generate ATPATP (energy)(energy)

• Dead Sea, Dead Sea, Great Salt Great Salt LakeLake inhabitantsinhabitants

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Thermoacidophiles Thermoacidophiles or Thermophilesor Thermophiles

• Live in Live in extremely hot extremely hot environmentsenvironments

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

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Kingdom Kingdom EubacteriaEubacteria

True BacteriaTrue Bacteria

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CharacteristicsCharacteristics

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

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

• May be May be aerobic or aerobic or anaerobicanaerobic

• Identified by Identified by Gram stainingGram staining

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Gram StainingGram Staining

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

• Bacteria treated with Bacteria treated with purple Crystal Violet & purple Crystal Violet & red Safranin stainsred Safranin stains

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

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Gram PositiveGram Positive

• Have Have thick layer thick layer of of peptidoglycanpeptidoglycan (protein-sugar (protein-sugar 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 antibiotics)antibiotics)

Clostridium Clostridium (lockjaw (lockjaw bacteria)bacteria)

Streptococcus Streptococcus (strep throat)(strep throat)Staphylococcus (Staphylococcus (staph staph

infections)infections)

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Gram Negative Gram Negative BacteriaBacteria

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

• Extra Extra thick layer of lipidsthick layer of lipids• Stain Stain pink or reddishpink or reddish• Hard to treatHard to treat with with

antibioticsantibiotics• Some Some photosyntheticphotosynthetic but but

make sulfur not oxygenmake sulfur not oxygen• Some Some fix nitrogenfix nitrogen for plants for plants

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Gram NegativeGram Negative

• Rhizobacteria Rhizobacteria grow in root grow in root nodules of nodules of legumeslegumes (soybeans, (soybeans, peanuts)peanuts)

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

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Gram NegativeGram Negative• Rickettsiae Rickettsiae are are

parasitic parasitic bacteria carried bacteria carried by ticksby ticks

• Cause Cause Lyme Lyme disease & disease & Rocky Mountain Rocky Mountain Spotted FeverSpotted Fever

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CyanobacteriaCyanobacteria

• Gram Gram negativenegative• PhotosyntheticPhotosynthetic• Called Called blue-green blue-green

bacteriabacteria• Contain Contain phycocyaninphycocyanin

(red-blue) pigments & (red-blue) pigments & chlorophyllchlorophyll

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

black, or blue-greenblack, or blue-green• May grow in May grow in chainschains

((OscillatoriaOscillatoria))• Have Have HeterocystsHeterocysts to help fix N to help fix N22

• First to re-enterFirst to re-enter devastated devastated areasareas

• Some cause Some cause EutrophicationEutrophication (use up O2 when die & (use up O2 when die & decompose in water)decompose in water)

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CyanobacteriaCyanobacteria

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SpirochetesSpirochetes• Gram Gram positivepositive• Flagella at each Flagella at each

endend• Move in Move in corkscrewcorkscrew

motionmotion• Some Some aerobicaerobic; ;

others others anaerobicanaerobic• May be May be free living, free living,

parasitic, or parasitic, or symbioticsymbiotic

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Enteric BacteriaEnteric Bacteria

• Gram Gram negativenegative• Can live in Can live in aerobic & aerobic &

anaerobicanaerobic habitats habitats• Includes Includes E. coliE. coli in in

intestinesintestines• Salmonella Salmonella – – causes causes

food poisoningfood poisoning

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ChemoautotrophsChemoautotrophs

• Gram Gram negativenegative• Obtain energy from Obtain energy from

minerals like ironminerals like iron• Found in Found in

freshwater pondsfreshwater ponds

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Nutrition, Nutrition, Respiration, Respiration,

and and ReproductionReproduction

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Modes of NutritionModes of Nutrition• Saprobes Saprobes – feed on – feed on

dead organic matterdead organic matter• ParasitesParasites – feed on a – feed on a

host cellhost cell• PhotoautotrophPhotoautotroph – use – use

sunlight to make foodsunlight to make food• ChemoautotrophChemoautotroph – –

oxidize inorganic matter oxidize inorganic matter such as iron or sulfur to such as iron or sulfur to make foodmake food

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Methods of Methods of RespirationRespiration

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

• Obligate AnaerobesObligate Anaerobes – die – die if Oif O22 is present (tetanus) is present (tetanus)

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

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Bacterial Bacterial RespirationRespiration

• AnaerobesAnaerobes carry on carry on fermentatifermentationon

• Aerobes Aerobes carry on carry on cellular cellular respirationrespiration

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ReproductionReproduction

• Bacteria reproduce Bacteria reproduce asexually by binary fissionasexually by binary fission

• 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 Cellular organism copies it’s genetic information then splits into two identical information then splits into two identical

daughter cellsdaughter cells

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Binary Fission Binary Fission E. E. colicoli

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ReproductionReproduction

• Bacteria reproduce Bacteria reproduce sexually by Conjugationsexually by Conjugation

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

• Held together byHeld together by pili pili• New cellsNew cells NOT identical NOT identical

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ConjugationConjugation

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Spore FormationSpore Formation• Form Form endosporeendospore

whenever when whenever when habitat conditions habitat conditions become become harsh harsh (little food)(little food)

• Able to Able to survive survive for long periods for long periods of timeof time as as endospermendosperm

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

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Transduction & Transduction & TransformationTransformation

• Genetically changeGenetically change bacteria bacteria• May become May become antibiotic antibiotic

resistantresistant• Transformed bacteriaTransformed bacteria pick pick

up pieces of DNA from dead up pieces of DNA from dead bacterial cellsbacterial cells

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

toxinstoxins• EndotoxinsEndotoxins released after released after

bacteria die (bacteria die (E. coliE. coli))• Exotoxins Exotoxins released by released by

Gram + bacteria (Gram + bacteria (C. C. tetanitetani))

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