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BacteriaBacteria

Structure and Structure and FunctionFunction

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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 3.5 billion years old

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CharacteristicsCharacteristics

• Bacteria are microscopic, Bacteria are microscopic, living cells that live living cells that live almost almost EVERYWHEREEVERYWHERE!!

• Bacteria are smaller than Bacteria are smaller than plant or animal cellsplant or animal cells

• Bacteria are Bacteria are prokaryoticprokaryotic since they do not have since they do not have membrane-bound internal membrane-bound internal structuresstructures

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CharacteristicsCharacteristics

• Some bacteria have a Some bacteria have a capsule around the cell wall, capsule around the cell wall, while others have an outer while others have an outer slime layerslime layer

• Many have whip-like tails Many have whip-like tails called called flagellaflagella to help them to help them movemove

• Most bacteria reproduce by Most bacteria reproduce by fissionfission

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Bacterial Cell

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

spirilla)spirilla)• Most are Most are heterotrophic heterotrophic (can’t (can’t

make their own food ~ make their own food ~ consumers or parasites),but consumers or parasites),but some are some are producersproducers (autotrophs) (autotrophs) that make their own foodthat make their own food

• May be May be aerobes (use oxygen) or aerobes (use oxygen) or anaerobes (do not use oxygen)anaerobes (do not use oxygen)

• Identified by Identified by Gram stainingGram staining

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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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Staphylococcus Staphylococcus causescauses

Skin infections Skin infections Pneumonia Pneumonia

Food poisoning Food poisoning Toxic shock syndrome Toxic shock syndrome

Blood poisoning (bacteremia)Blood poisoning (bacteremia)

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BacillusBacillus ~ Lactobacillus acidophilus is generally considered to be beneficial because it produces vitamin K, lactase, and anti-microbial substances

~ E. coli (+O157:H7)

~ Anthrax

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StreptobacilliStreptobacilli

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SpirillumSpirillum

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SpirochetesSpirochetes

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LeptospiraLeptospiraOutbreaks of leptospirosis are usually caused by Outbreaks of leptospirosis are usually caused by exposure to water contaminated with the urine of exposure to water contaminated with the urine of

infected animals. infected animals.

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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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TWOTWO Kingdoms of Kingdoms of BacteriaBacteria

Eubacteria (larger) - Eubacteria (larger) - GGrouped rouped according to cell shape and according to cell shape and structure, the way they obtain food, structure, the way they obtain food, the type of food they eat, the wastes the type of food they eat, the wastes they produce, the method they use they produce, the method they use to move, and whether or not they to move, and whether or not they use oxygenuse oxygen

Archaebacteria -Archaebacteria -FFound in ound in extreme locations and are divided extreme locations and are divided into groups based on where they live into groups based on where they live or how they get their energyor how they get their energy

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EUBACTERIAEUBACTERIACyanobacteriaCyanobacteria – produce their – produce their

own food and are commonly own food and are commonly called blue-green bacteriacalled blue-green bacteria -May be yellow, -May be yellow, blackblack, or , or

redred in color in color -Provide food and oxygen -Provide food and oxygen for aquatic life; for aquatic life; however, an over-however, an over- abundance produces a abundance produces a bloombloom – HARMFUL!! – HARMFUL!!Consumer eubacteriaConsumer eubacteria are grouped are grouped

by cell wall thickness or by cell wall thickness or thinness and how they STAIN!thinness and how they STAIN!

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CyanobacteriaCyanobacteria

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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 peptidoglycanof peptidoglycan (protein-sugar (protein-sugar complex)complex)

• Single lipid layerSingle lipid layer• 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, e.g., streptomycin antibiotics, e.g., streptomycin and tetracycline)and tetracycline)

Clostridium Clostridium (lockjaw bacteria)(lockjaw 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 bacteria parasitic bacteria carried by tickscarried by ticks

• CauseCause Lyme Lyme disease & Rocky disease & Rocky Mountain Spotted Mountain Spotted FeverFever

• Chlamydia Chlamydia trachomatistrachomatis causes causes nongonococcal nongonococcal urethritis, or urethritis, or chlamydia, an STIchlamydia, an STI

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EubacteriaEubacteria

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ARCHAEBACTERIARCHAEBACTERIAA

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

• 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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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 ocean cracks on ocean floor that leak floor that leak acidacid

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ArchaebacteriaArchaebacteria

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Useful BacteriaUseful Bacteria

• Most bacteria are Most bacteria are HELPFULHELPFUL, , rather than harmfulrather than harmful

• Bacteria are necessary for Bacteria are necessary for human human healthhealth…many aid …many aid digestion and some produce digestion and some produce vitamins, e.g., vitamin K vitamins, e.g., vitamin K (necessary for blood clot (necessary for blood clot formation)formation)

• Some bacteria produce Some bacteria produce antibioticsantibiotics, which are used to , which are used to treat diseasestreat diseases

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Useful BacteriaUseful Bacteria

• Bacteria help keep nature in Bacteria help keep nature in balancebalance– Saprophytes Saprophytes – use dead – use dead

organisms as food and energy organisms as food and energy sources, thus recycling sources, thus recycling nutrients for other organismsnutrients for other organisms

– Nitrogen-fixing bacteriaNitrogen-fixing bacteria in soil in soil and plant roots change and plant roots change nitrogen from the air to a form nitrogen from the air to a form plants and animals can useplants and animals can use

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Useful BacteriaUseful Bacteria• Some bacteria can Some bacteria can

degrade oil and degrade oil and are used toare used to clean clean up up oil spills – oil spills – BIOREMEDIATIONBIOREMEDIATION

• Some bacteria Some bacteria break waste down break waste down into harmless into harmless compounds and compounds and some eat some eat pollutants!pollutants!

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Useful BacteriaUseful Bacteria• Other uses for Other uses for

bacteria include bacteria include making foods, like making foods, like dairy products, dairy products, e.g., yogurt, e.g., yogurt, cheese, and cheese, and buttermilk, as buttermilk, as well as well as sauerkraut, and sauerkraut, and picklespickles

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Useful BacteriaUseful Bacteria• Bacteria are used in Bacteria are used in

industry ~ grown in industry ~ grown in bioreactorsbioreactors to make to make medicinesmedicines

• Methane-producingMethane-producing bacteria can digest bacteria can digest wastes and provide a wastes and provide a source of fuelsource of fuel

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Pathogenic Pathogenic BacteriaBacteria

• Bacteria that cause disease Bacteria that cause disease are called bacterial are called bacterial pathogenspathogens– Toxins, or poisons are made Toxins, or poisons are made

by someby some– Some form endospores when Some form endospores when

environmental conditions are environmental conditions are not favorablenot favorable

– Pasteurization kills most Pasteurization kills most harmful bacteria in foodharmful bacteria in food

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Pathogenic Pathogenic BacteriaBacteria

– Vaccines can prevent Vaccines can prevent SOME bacterial infectionsSOME bacterial infections•Vaccines are made from Vaccines are made from damaged or DEAD bacterial damaged or DEAD bacterial cellscells

•Once injected, they enable Once injected, they enable white blood cells in the body white blood cells in the body to recognize a particular to recognize a particular type of bacteria and attack type of bacteria and attack it if it appears at a later timeit if it appears at a later time