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Microbes Microbes
Bacteria and ProtistsBacteria and Protists
Three Domain Organizational Scheme Three Domain Organizational Scheme
Six Kingdoms
PROKARYA
Sizes of Prokaryotic Cells
Non-living entities made of genetic
material + protective coat
Characteristics of Characteristics of Bacteria and ArchaeaBacteria and Archaea
• ProkaryoticProkaryotic• Single CelledSingle Celled• Cell wall made of peptidoglycanCell wall made of peptidoglycan• May be covered with capsuleMay be covered with capsule• Use flagellum for movementUse flagellum for movement
– Made of unique protein, not microtubulesMade of unique protein, not microtubules
• Many nutritional modesMany nutritional modes– Heterotrophic or AutotrophicHeterotrophic or Autotrophic– Use of light energy or chemical energyUse of light energy or chemical energy
Characteristics of Characteristics of Bacteria and ArchaeaBacteria and Archaea
• Infolded plasma membranes for Infolded plasma membranes for respiration or photosynthesisrespiration or photosynthesis
• Single, circular chromosomeSingle, circular chromosome
• May contain extrachromosomal May contain extrachromosomal plasmidsplasmids
• Reproduce by binary fission Reproduce by binary fission
• Gene transfer with conjugation Gene transfer with conjugation
Binary FissionBinary Fission
Conjugation: Transfer of DNA From Donor to Recipient
Sex PilusSex PilusSex PilusSex Pilus
DonorDonorDonorDonor
RecipientRecipientRecipientRecipient
ArchaeaArchaea• Unique lipid membranes, Unique lipid membranes,
cell walls, and ribosomal RNAcell walls, and ribosomal RNA• MethanogensMethanogens
– Convert COConvert CO22 to methane to methane– Found in swamps, hot springs, Found in swamps, hot springs,
vent communities, cow stomachsvent communities, cow stomachs
• Halophiles - survive in a Halophiles - survive in a concentrated salt environmentconcentrated salt environment
• Thermophiles - thrive in a hot Thermophiles - thrive in a hot environmentenvironment
Prokaryotic MetabolismProkaryotic Metabolism• Autotrophic (self-feeder)Autotrophic (self-feeder)
– PhotoautotrophsPhotoautotrophs• Cyanobacteria—use COCyanobacteria—use CO22, ,
H H22O, release OO, release O22
– ChemoautotrophsChemoautotrophs• sulfur bacteria-- use COsulfur bacteria-- use CO22, ,
H H22S, release sulfurS, release sulfur• SulfolobusSulfolobus—archaean —archaean
thermophile that oxidizes thermophile that oxidizes sulfursulfur
Prokaryotic MetabolismProkaryotic Metabolism• Heterotrophic (other-feeder)Heterotrophic (other-feeder)
– PhotoheterotrophsPhotoheterotrophs• Use light energy + carbon from Use light energy + carbon from
organic compoundsorganic compounds• Purple non-sulfur bacteriaPurple non-sulfur bacteria
– ChemoheterotrophsChemoheterotrophs• Use organic compounds for chemical Use organic compounds for chemical
energy and sources of carbon energy and sources of carbon • Largest group of prokaryotes Largest group of prokaryotes
Prokaryotic MetabolismProkaryotic Metabolism• ChemoheterotrophsChemoheterotrophs
– Can beCan be• Pathogenic (disease causing)Pathogenic (disease causing)
– Some secrete ExotoxinsSome secrete Exotoxins– Others release EndotoxinsOthers release Endotoxins– Some form Endospores Some form Endospores
resistant to heat and dessicationresistant to heat and dessication
S. mutans
S. pyrogenes
Anthrax
Prokaryotic MetabolismProkaryotic Metabolism• ChemoheterotrophsChemoheterotrophs
– Can beCan be• Non-pathogenicNon-pathogenic• Decomposers-live on dead organic matterDecomposers-live on dead organic matter• Nitrogen-fixing bacteria- convert nitrogen gas into Nitrogen-fixing bacteria- convert nitrogen gas into
compounds that plants can usecompounds that plants can use
Applying Your KnowledgeApplying Your Knowledge
Which type of metabolism is used by Which type of metabolism is used by
A.A. Flesh-eating bacteria? Flesh-eating bacteria?
B.B. Bacteria that use COBacteria that use CO22 + light energy to + light energy to produce glucose?produce glucose?
C.C. Bacteria that COBacteria that CO22 ++ chemical energy from chemical energy from sulfur to produce glucose? sulfur to produce glucose?
1.1. PhotoautotrophPhotoautotroph2.2. ChemoautotrophChemoautotroph3.3. PhotoheterotrophPhotoheterotroph4.4. ChemoheterotrophChemoheterotroph
Characteristics of ProtistaCharacteristics of Protista
• EukaryoticEukaryotic• Usually Single CelledUsually Single Celled• Live in moist environmentsLive in moist environments• Many nutritional modesMany nutritional modes
– HeterotrophicHeterotrophic– AutotrophicAutotrophic– CombinationCombination
• Sexual and asexual reproduction Sexual and asexual reproduction
Protist ReproductionProtist Reproduction
AsexualAsexual reproduction Asexual reproduction
occurs by mitosis.occurs by mitosis.
SexualSexual reproduction Sexual reproduction involves the exchange involves the exchange of genetic material of genetic material across a cytoplasmic across a cytoplasmic bridge. bridge.
Distinctive Features of ProtistsDistinctive Features of Protists
• Modified MitochondriaModified Mitochondria– Diplomonads: Diplomonads:
mitochondria lack DNA mitochondria lack DNA and electron transport and electron transport chainchain
– Parabasalids: modified Parabasalids: modified mitochondria generate mitochondria generate energy anaerobicallyenergy anaerobically
Giardia
Trichomonas
Distinctive Features of ProtistsDistinctive Features of Protists
• Flagella with crystalline rodFlagella with crystalline rod– EuglenozoansEuglenozoans
Trypanosoma Euglena
Which one is heterotrophic?Which one is heterotrophic?Which one is autotrophic?Which one is autotrophic?
Distinctive Features of ProtistsDistinctive Features of Protists• Membrane-bound Sacs beneath plasma Membrane-bound Sacs beneath plasma
membranemembrane
– AlveolatesAlveolates• Sacs help stabilize cell surface or regulate Sacs help stabilize cell surface or regulate
water and iron contentwater and iron content• DinoflagellatesDinoflagellates
“Red tide”
Distinctive Features of ProtistsDistinctive Features of Protists• Membrane-bound Sacs beneath plasma Membrane-bound Sacs beneath plasma
membranemembrane
– AlveolatesAlveolates• CiliatesCiliates• ApicomplexansApicomplexans
Didinium feeding on Paramecium
Plasmodium inside red blood cells
Distinctive Features of ProtistsDistinctive Features of Protists• Hairy and Smooth FlagellaHairy and Smooth Flagella
– StramenopilesStramenopiles• Water MoldsWater Molds• DiatomsDiatoms• Brown AlgaeBrown Algae
DiatomsSargassum
Water mold Water mold
Distinctive Features of ProtistsDistinctive Features of Protists• Lobe-Shaped PseudopodiaLobe-Shaped Pseudopodia
– AmoebozoansAmoebozoans• AmoebasAmoebas• Plasmodial Slime MoldsPlasmodial Slime Molds• Cellular Slime MoldsCellular Slime Molds
AmoebaPlasmodial Slime Mold
Single, amoeba-like cells emerge from spores, crawl, and feed.
When food is scarce, cells aggregate into slug-like mass called a pseudoplasmodium.
Pseudoplasmodium migrates toward light, forms fruiting bodies that produce spores.
fruiting bodies
spores
nucleus
The Life Cycle of a Cellular Slime MoldThe Life Cycle of a Cellular Slime Mold
Distinctive Features of ProtistsDistinctive Features of Protists• Thread-Like PseudopodiaThread-Like Pseudopodia
– ForaminiferansForaminiferans
– RadiolariansRadiolarians
Foraminiferan
Radiolarian
Distinctive Features of ProtistsDistinctive Features of Protists
• Algal Groups similar to Land PlantsAlgal Groups similar to Land Plants
– Green AlgaeGreen Algae
Ulva
Volvox
Chlamydomonas
Distinctive Features of ProtistsDistinctive Features of Protists• Algal Groups similar to Land PlantsAlgal Groups similar to Land Plants
– Red AlgaeRed Algae
Applying Your KnowledgeApplying Your Knowledge
Which cellular characteristic is distinctive for Which cellular characteristic is distinctive for
A.A. Foraminiferans? Foraminiferans?
B.B. Amoebas?Amoebas?
C.C. Ciliates like Ciliates like ParameciumParamecium? ?
D.D. Diplomonads like Diplomonads like GiardiaGiardia??
1.1. Modified MitochondriaModified Mitochondria2.2. Alveolate sacsAlveolate sacs3.3. Lobe-shaped PseudopodiaLobe-shaped Pseudopodia4.4. Thread-like PseudopodiaThread-like Pseudopodia
