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Introduction to Microbiology

Introduction to Microbiology

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Introduction to Microbiology

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  1. Introduction to Microbiology The Microbial World and You

  2. What Are Microorganisms? • Minute living things • Too small to be seen with the unaided eye • Members of several different groups

  3. Different groups of microorganisms • bacteria • fungi • protozoa • microscopic algae

  4. Ways that microbes affect us • cycling chemicals through our environment • serve as the basis of food chains • aid normal functioning of animal systems • commercial applications • cause disease

  5. Chemical elements are cycled by microbes • by photosynthesis: C, H, O • by chemosynthesis: C, H, N, S, P • by aerobic respiration: C, H, O • by anaerobic respiration: C, H, N, S, P • by fermentation: C, H, O

  6. Basis of food chains • phytoplankton (producers) • zooplankton (first level of consumers)

  7. Aiding functioning of animal systems • aiding in the digestion of ruminants and termites • synthesizing B vitamins and vitamin K

  8. Commercial applications of microbes • normal synthesis of chemical products • food production • synthesis of abnormal products

  9. Chemical products normally synthesized by microbes • acetone • organic acids • enzymes • alcohols • drugs

  10. vinegar sauerkraut pickles alcoholic beverages green olives soy sauce buttermilk cottage cheese cheese yogurt bread sourdough bread Foods produced by microbes

  11. Products of genetically modified microorganisms • human insulin and human growth hormone • digestive aids • cellulose • drain cleaner

  12. Some microbes cause disease • pathogens (disease-producing microbes) • opportunists (microbes that do not normally cause disease, but my do so under certain conditions)

  13. Naming Microorganisms • genus name is first and is always capitalized • species name (specific epithet) follows the genus name and is never capitalized • genus and species names are italicized • example: Staphylococcus aureus • the cursive indicator of italics is underlining

  14. Family Micrococcaceae • Micro- means very tiny • Family members are found on human skin • Genus Staphylococcus can fermentsugars, and, therefore, can grow with or without oxygen • Genus Micrococcus cannot ferment sugars, and, therefore, cannot grow without oxygen

  15. Genus Staphylococcus • Staphylo- means clusters of cells • coccus- means spherical cells • Staphylococcus means clusters of very tiny, spherical cells • aureus means golden-colored colonies • Staphylococcus aureus means golden-colored colonies of clusters of very tiny, spherical cells

  16. Genus Staphylococcus, continued • Staphylococcus aureus: golden-colored colonies • S. epidermidis: normal microbe of the skin • S. saprophyticus: a microbe that causes decay of organic matter • After using the full genus name once in a paragraph, it is then permissible to abbreviate that genus name.

  17. Genus Micrococcus • Micrococcus luteus: bright mustard-yellow colonies of clusters of very tiny, spherical cells • M. roseus: rose-colored colonies

  18. Classifications of Microorganisms • Prokaryotes: cells lack nuclei, membrane-bound organelles, sterols and carbohydrates in membranes • Eukaryotes: cells possess nuclei, membrane-bound organelles, sterols and carbohydrates in the membranes

  19. Prokaryotes • Bacteria: most of the procaryotes, cell walls contain peptidoglycan and D amino acids, a few bacteria are pathogenic. • Archea: may lack cell walls or have unusual cell walls composed of polysaccharides, proteins, and pseudomurein, but never peptidoglycan. Archea are often found in extreme environments.

  20. Bacteria • Cell morphology: cocci, bacilli, spirilli, star-shaped, squares • Cell arrangement: individual, pairs, chains, tetrads, sarcina (8), (grape-like) clusters • Cell walls contain different amounts of peptidoglycan and other substances which result in characteristic staining properties such as Gram-positive, Gram-negative, and Acid-fast cells. • Many bacteria are motile by means of flagella • Nutritional requirements are extremely diverse

  21. Eukaryotes • Algae: photosynthetic unicellular or simple multicellular, mostly aquatic, organisms with cell walls of cellulose • Fungi: saprophytic or opportunistic unicellular (yeasts) or simple multicellular organisms with cell walls of chitin • Protozoa: unicellular, mostly motile organisms without cell walls, that absorb or ingest nutrients • Helminths: parasitic worms: flatworms and roundworms

  22. VIRUSES • Living? or Nonliving? • Contain a core of one nucleic acid only (either DNA or RNA) • Nucleic acid core is surrounded by a protein coat called a capsid • Viruses are host-specific: animal, plant, bacterial • Some animal viruses possess envelopes