Transcript Amoeba
Microbes Bacteria and Protists Three Domain Organizational Scheme PROKARYA Six Kingdoms Sizes of Prokaryotic Cells Non-living entities made of genetic material + protective coat Characteristics of Bacteria and Archaea • • • • • Prokaryotic Single Celled Cell wall made of peptidoglycan May be covered with capsule Use flagellum for movement – Made of unique protein, not microtubules • Many nutritional modes – Heterotrophic or Autotrophic – Use of light energy or chemical energy Characteristics of Bacteria and Archaea • Infolded plasma membranes for respiration or photosynthesis • Single, circular chromosome • May contain extrachromosomal plasmids • Reproduce by binary fission • Gene transfer with conjugation Binary Fission Conjugation: Transfer of DNA From Donor to Recipient Donor Recipient Sex Pilus Archaea • Unique lipid membranes, cell walls, and ribosomal RNA • Methanogens – Convert CO2 to methane – Found in swamps, hot springs, vent communities, cow stomachs • Halophiles - survive in a concentrated salt environment • Thermophiles - thrive in a hot environment Prokaryotic Metabolism • Autotrophic (self-feeder) – Photoautotrophs • Cyanobacteria—use CO2, H2O, release O2 – Chemoautotrophs • sulfur bacteria-- use CO2, H2S, release sulfur • Sulfolobus—archaean thermophile that oxidizes sulfur Prokaryotic Metabolism • Heterotrophic (other-feeder) – Photoheterotrophs • Use light energy + carbon from organic compounds • Purple non-sulfur bacteria – Chemoheterotrophs • Use organic compounds for chemical energy and sources of carbon • Largest group of prokaryotes Prokaryotic Metabolism • Chemoheterotrophs – Can be • Pathogenic (disease causing) – Some secrete Exotoxins – Others release Endotoxins – Some form Endospores resistant to heat and dessication Anthrax S. mutans S. pyrogenes Prokaryotic Metabolism • Chemoheterotrophs – Can be • Non-pathogenic • Decomposers-live on dead organic matter • Nitrogen-fixing bacteria- convert nitrogen gas into compounds that plants can use Applying Your Knowledge 1. 2. 3. 4. Photoautotroph Chemoautotroph Photoheterotroph Chemoheterotroph Which type of metabolism is used by A. Flesh-eating bacteria? B. Bacteria that use CO2 + light energy to produce glucose? C. Bacteria that CO2 + chemical energy from sulfur to produce glucose? Characteristics of Protista • • • • Eukaryotic Usually Single Celled Live in moist environments Many nutritional modes – Heterotrophic – Autotrophic – Combination • Sexual 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 Mitochondria – Diplomonads: mitochondria lack DNA and electron transport chain Giardia Trichomonas – Parabasalids: modified mitochondria generate energy anaerobically Distinctive Features of Protists • Flagella with crystalline rod – Euglenozoans Trypanosoma Euglena Which one is heterotrophic? Which one is autotrophic? Distinctive Features of Protists • Membrane-bound Sacs beneath plasma membrane – Alveolates • Sacs help stabilize cell surface or regulate water and iron content • Dinoflagellates “Red tide” Distinctive Features of Protists • Membrane-bound Sacs beneath plasma membrane – Alveolates • Ciliates • Apicomplexans Didinium feeding on Paramecium Plasmodium inside red blood cells Distinctive Features of Protists • Hairy and Smooth Flagella – Stramenopiles • Water Molds • Diatoms • Brown Algae Water mold Diatoms Sargassum Distinctive Features of Protists • Lobe-Shaped Pseudopodia – Amoebozoans • Amoebas • Plasmodial Slime Molds • Cellular Slime Molds Plasmodial Slime Mold Amoeba The Life Cycle of a Cellular Slime Mold Pseudoplasmodium migrates toward light, forms fruiting bodies that produce spores. spores fruiting bodies nucleus Single, amoebalike cells emerge from spores, crawl, and feed. When food is scarce, cells aggregate into sluglike mass called a pseudoplasmodium. Distinctive Features of Protists • Thread-Like Pseudopodia – Foraminiferans – Radiolarians Foraminiferan Radiolarian Distinctive Features of Protists • Algal Groups similar to Land Plants – Green Algae Chlamydomonas Ulva Volvox Distinctive Features of Protists • Algal Groups similar to Land Plants – Red Algae Applying Your Knowledge 1. 2. 3. 4. Modified Mitochondria Alveolate sacs Lobe-shaped Pseudopodia Thread-like Pseudopodia Which cellular characteristic is distinctive for A. Foraminiferans? B. Amoebas? C. Ciliates like Paramecium? D. Diplomonads like Giardia?