Topic 1-7.docx - Topic 1 Overview of Microbiology Overview...

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Topic 1: Overview of Microbiology Overview Microbes in our lives Benefits of microorganisms Naming and classifying microorganisms o Nomenclature o Types of microorganisms Bacteria Archaea Fungi Protozoa Viruses
Learning objectives Define microbiology Biology is the study of living organisms Microbiology is the study of living organisms that individually cannot be seen with the naked eye List and differentiate the major characteristics of the organisms that are studied in microbiology Organisms are referred to as microorganisms or microbes Bacteria o Very small (2-8 m by 0.2-2 m) o Single-celled (unicellular) o Prokaryotic (genetic material not enclosed in a nuclear membrane) o Enclosed in cell walls composed in peptidoglycan o Reproduce by binary fission (divide into 2 equal cells) o Shapes: bacillus (rod), coccus (spherical), spiral o Form: pairs, chains, clusters o Pathogens include: M. tuberculosis, E. coli O157:H7, S. aureus, S. pyogenes Archaea o Single-celled o Prokaryotic o Lack peptidoglycan in cell walls o Often found in extreme environments o 3 main groups: methanogens (produce methane), extreme halophiles (live in high salt), extreme thermophiles (live in hot surfaces, like sulfurous water) o Not known to cause human diseases Fungi o Eukaryotic (genetic material is enclosed within a membrane-bound nucleus) o Unicellular or multicellular o Includes yeasts, mold and mushrooms o Yeasts Unicellular Oval shaped Some are beneficial (like S. cerevisiae baker’s yeast) Important in research C. albicans causes mouth and vaginal infections o Molds Filamentous fungi Widespread Each filament is called a hypha Filaments form visible mass called mycelium
Reproduce by spores Some cause spoilage of foods (bread, fruit) Some produce antibiotics and other drugs Opportunistic pathogens o Some fungi cause diseases or mycoses o Five types of infections (systemic, subcutaneous, cutaneous, superficial, opportunistic) Protozoa o Unicellular o Eukaryotic o Found in water, moist environments o Motile using cilia, flagella, pseudopods (false feet) o Some cause disease o Plasmodium causes malaria Parasitic worms o Helminths (flatworms and roundworms) o Animal parasites o Multicellular o Eukaryotic o Parasitic, belong to two phyla Platyhelminthes (flatworms) Nematoda (roundworms Viruses o Very small, seen only using an electron microscope o Acellular (not cellular) o Nucleic acid core either DNA or RNA o Protein coat o May have lipid envelope o Must replicate within a living host cell (parasites) and use host machinery to reproduce o Viruses are only “living” when they multiply within host cells they infect o They infect: bacteria, plants, animals (including humans) o Viruses of medical significance include influenza virus, hepatitis virus A &C, HIV, noroviruses, Ebola virus Describe some of the destructive and beneficial actions of the microorganisms Most microorganisms are harmless Many are beneficial Benefits include: o Energy/ environment Biofuel production, like CH 4 (methane), ethanol

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