Microbes Microbes Bacteria and Protists

Three Domain Organizational Scheme Six Kingdoms PROKARYA

Sizes of Prokaryotic Cells Non-living entities made of genetic material + protective coat

Characteristics of Bacteria 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 microtubules Many nutritional modesMany nutritional modes –Heterotrophic or Autotrophic –Use of light energy or chemical energy

Characteristics of Bacteria and Archaea Infolded plasma membranes for respiration or photosynthesisInfolded plasma membranes for respiration or photosynthesis Single, circular chromosomeSingle, circular chromosome May contain extrachromosomal plasmidsMay contain extrachromosomal plasmids Reproduce by binary fissionReproduce by binary fission Gene transfer with conjugationGene transfer with conjugation

Binary Fission

Conjugation: Transfer of DNA From Donor to Recipient Sex Pilus Donor Recipient

Archaea Unique lipid membranes, cell walls, and ribosomal RNAUnique lipid membranes, cell walls, and ribosomal RNA MethanogensMethanogens –Convert CO 2 to methane –Found in swamps, hot springs, vent communities, cow stomachs Halophiles - survive in a concentrated salt environmentHalophiles - survive in a concentrated salt environment Thermophiles - thrive in a hot environmentThermophiles - thrive in a hot environment

Prokaryotic Metabolism Autotrophic (self-feeder)Autotrophic (self-feeder) –Photoautotrophs Cyanobacteria—use CO 2, H 2 O, release O 2Cyanobacteria—use CO 2, H 2 O, release O 2 –Chemoautotrophs sulfur bacteria-- use CO 2, H 2 S, release sulfursulfur bacteria-- use CO 2, H 2 S, release sulfur Sulfolobus—archaean thermophile that oxidizes sulfurSulfolobus—archaean thermophile that oxidizes sulfur

Prokaryotic Metabolism Heterotrophic (other-feeder)Heterotrophic (other-feeder) –Photoheterotrophs Use light energy + carbon from organic compoundsUse light energy + carbon from organic compounds Purple non-sulfur bacteriaPurple non-sulfur bacteria –Chemoheterotrophs Use organic compounds for chemical energy and sources of carbonUse organic compounds for chemical energy and sources of carbon Largest group of prokaryotesLargest group of prokaryotes

Prokaryotic Metabolism ChemoheterotrophsChemoheterotrophs –Can be Pathogenic (disease causing)Pathogenic (disease causing) –Some secrete Exotoxins –Others release Endotoxins –Some form Endospores resistant to heat and dessication S. mutans S. pyrogenes Anthrax

Prokaryotic Metabolism ChemoheterotrophsChemoheterotrophs –Can be Non-pathogenicNon-pathogenic Decomposers-live on dead organic matterDecomposers-live on dead organic matter Nitrogen-fixing bacteria- convert nitrogen gas into compounds that plants can useNitrogen-fixing bacteria- convert nitrogen gas into compounds that plants can use

Applying Your Knowledge Which type of metabolism is used by A.Flesh-eating bacteria? B.Bacteria that use CO 2 + light energy to produce glucose? C.Bacteria that CO 2 + chemical energy from sulfur to produce glucose? 1.Photoautotroph 2.Chemoautotroph 3.Photoheterotroph 4.Chemoheterotroph

Characteristics of Protista EukaryoticEukaryotic Usually Single CelledUsually Single Celled Live in moist environmentsLive in moist environments Many nutritional modesMany nutritional modes –Heterotrophic –Autotrophic –Combination Sexual and asexual reproductionSexual and asexual reproduction

Protist Reproduction Asexual Asexual reproduction occurs by mitosis. Sexual Sexual reproduction involves the exchange of genetic material across a cytoplasmic bridge.

Distinctive Features of Protists Modified MitochondriaModified Mitochondria –Diplomonads: mitochondria lack DNA and electron transport chain –Parabasalids: modified mitochondria generate energy anaerobically Giardia Trichomonas

Distinctive Features of Protists Flagella with crystalline rodFlagella with crystalline rod –Euglenozoans Trypanosoma Euglena Which one is heterotrophic? Which one is autotrophic?

Distinctive Features of Protists Membrane-bound Sacs beneath plasma membraneMembrane-bound Sacs beneath plasma membrane –Alveolates Sacs help stabilize cell surface or regulate water and iron contentSacs help stabilize cell surface or regulate water and iron content DinoflagellatesDinoflagellates “Red tide”

Distinctive Features of Protists Membrane-bound Sacs beneath plasma membraneMembrane-bound Sacs beneath plasma membrane –Alveolates CiliatesCiliates ApicomplexansApicomplexans Didinium feeding on Paramecium Plasmodium inside red blood cells

Distinctive Features of Protists Hairy and Smooth FlagellaHairy and Smooth Flagella –Stramenopiles Water MoldsWater Molds DiatomsDiatoms Brown AlgaeBrown Algae Diatoms Sargassum Water mold

Distinctive Features of Protists Lobe-Shaped PseudopodiaLobe-Shaped Pseudopodia –Amoebozoans AmoebasAmoebas Plasmodial Slime MoldsPlasmodial Slime Molds Cellular Slime MoldsCellular Slime Molds Amoeba Plasmodial 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 Mold

Distinctive Features of Protists Thread-Like PseudopodiaThread-Like Pseudopodia –Foraminiferans –Radiolarians Foraminiferan Radiolarian

Distinctive Features of Protists Algal Groups similar to Land PlantsAlgal Groups similar to Land Plants –Green Algae Ulva Volvox Chlamydomonas

Distinctive Features of Protists Algal Groups similar to Land PlantsAlgal Groups similar to Land Plants –Red Algae

Applying Your Knowledge Which cellular characteristic is distinctive for A.Foraminiferans? B.Amoebas? C.Ciliates like Paramecium? D.Diplomonads like Giardia? 1.Modified Mitochondria 2.Alveolate sacs 3.Lobe-shaped Pseudopodia 4.Thread-like Pseudopodia