Microorganisms Chapter 17 (556-560, 564-565) Chapter 31 (608-623) Chapter 28 (549-569) Microorganisms Bacteria Cyanobacteria Fungi Protists Bacteria Are Wee 1 mm = 1000000 Largest prokaryote is 100000 Epulopiscium fishelsoni 600 μm!!! (= 0.6 mm) Size (nm) 10000 Average bacteria range from 1-5 μm 1 μm = 1000 Smallest bacteria are the Mycoplasma 120-250 nm 100 1
Bacterial Cell Shapes Coccus Staphylococcus aureus Bacillus Escherichia coli Coccobacillus Brucella abortus Spiral Helicobacter pylori Pleomorphic Mycobacteria Lack a rigid cell wall Bacterial Arrangements Pairs Neisseria gonorrhoeae Clusters Staphylococcus aureus Chains Streptococcus pneumoniaea Random Bacterial Structures Cell Membrane Cell Wall Outer membrane Internal Structures Nucleoid Ribosomes External Structures Capsule Pili Flagella No organelles 2
Cell Division in Bacteria Binary fission Continuous DNA synthesis Continuous growth Cyanobacteria Photosynthetic prokaryotes Internal membrane structures Anabaena Heterocysts Nitrogen fixation Nucleariids Predecessor to all fungi An opisthokont protist 3
The Fungi Not just mushrooms! Hyphae Tubular Branched Mycelium Aggregation Animal-like Cell walls Glycogen Fats Biology of Fungi Absorptive heterotrophs Saprophytic Parasitic Predatory Arthrobotrys Fungal Life Cycle Haplontic life cycle PLASMOGAMY (fusion of cytoplasm) Heterokaryotic stage Spore-producing structures Spores ASEXUAL REPRODUCTION Mycelium KARYOGAMY (fusion of nuclei) Zygote SEXUAL REPRODUCTION GERMINATION Diploid zygote Haploid spores Haploid mycelium Plasmogamy Heterokaryotic Karyogamy GERMINATION Spores MEIOSIS 4
Fungal Spores Common reproductive cell Produced by: Meiosis sexual Mycelia Mitosis asexual Divide by mitosis Sporangia Spores Sporangium Zygosporangium MEIOSIS KARYOGAMY Diploid nuclei Mycelium Fungal Gametes Mitosis Heterokaryotic mycelium Isogametes + versus Mating type (+) PLASMOGAMY Mating type ( ) Gametangia with haploid nuclei Young zygosporangium (heterokaryotic) Zygosporangium Fungal Phyla Chytridiomycota Zygomycetes Glomeromycetes Ascomycetes Basidiomycetes 5
Phylum Chytridiomycota Ancestral fungi Most are aquatic Flagella Gametes Zoospores No mycelia Rhizoids Phylum Zygomycetes Aseptate hyphae Coenocytic Asexual reproduction Spores released from sporangia Sexual reproduction and + strains combine Resilient zygosporangium Karyogamy & meiosis Black bread mold (Lab 6) Phylum Glomeromycetes Very small group Very significant group Arbuscular mycorrhizae 90-95% 95% of plants 6
Phylum Ascomycetes Septate hyphae The sac fungi Fruiting bodies Ascocarp Sporangia (asci) Meiosis Mitosis 8 ascospores Asexual spores Conidia Phylum Basidiomycetes Septate hyphae The club fungi Fruiting bodies Basidiocarp Sporangia (basidia) Meiosis 4 basidiospores Long-lived dikaryotic stage Decomposition Saprophytic Non-living food source Leaf litter Locked in nutrients Insoluble 7
Extracellular Digestion Hydrolytic enzymes Absorptive heterotrophs Parasitic Fungi Heterotroph Living organisms (host) Dutch elm disease Mycelium infects xylem Scarring Athletes foot Practical Mycology Antibiotics 3R*,4S*,5S*,6R*,7R*, 9R*,11R*, 12R*,13S*,14R*)-4-[(2,6-Dideoxy-3-C-methyl-3-O-methylα-L-ribo-hexopyranosyl)-oxy]-14-ethyl-7,12,13-trihydroxy-3, 5, 7, 9,11,13-hexamethyl-6- [[3,4,6-trideoxy-3-(dimethylamino)-β-D-xylo-hexopyranosyl]oxy]oxacyclotetradecane- 2,10-dione Food 8
Autotrophic Protists Photosynthetic Algae All have chloroplasts Source? Euglenoids Plant-like Chloroplasts Photosynthesis Animal-like No cell wall Ingest nutrients Mixotrophs Long flagellum Eyespot Short flagellum Contractile vacuole Chloroplast Plasma membrane Pellicle Evolution of Eukaryotes Prokaryotic ancestor Plasma membrane invaginates Remember Anabaena Internal membranes Endomembrane theory 9
Endosymbiotic Theory Serial endosymbiosis Two possible mechanisms 1. Ingest but don t kill 2. Infect but don t kill First event Heterotrophic prokaryote Mitochondrion Endosymbiotic Theory Second event Autotrophic prokaryote Chloroplast Endosymbiotic Theory Third event Autotrophic eukaryote Chloroplast Evidence? 10
The Algae Grouped by colour Pigments in chloroplast Chlorophyll a Accessory pigments Fucoxanthin Phycoerythrin Chlorophyll b Brown Algae Red Algae Green Algae Algal Structure Overall structure Similarities to the land plants Blades No true leaves Stipe No true stems Holdfast No true roots Algal Structure Predecessor of land plants Many similarities Structure and function Cosmarium Cell Wall Land plant Plasma Membrane Nucleus Plant Vacuole Chloroplast Pyrenoid 11
Algal Life Cycles Haplontic or Alternation of generations No heterokaryotic stage Chlamydomonas Gametes (n) + + Zoospore Mature cell (n) FERTILIZATION Zygote (2n) MEIOSIS Lichens Symbioses Mycobiont Ascomycetes Photobiont Alga, cyanobacteria 12