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Introduction to Microorganisms

Introduction to Microorganisms. 1. Lesson Objectives:. Define microbiology. List the organisms included in the field of microbiology . Discuss the role microorganisms play in the environment, the food industry and the medical field.

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Introduction to Microorganisms

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  1. Introduction to Microorganisms 1

  2. Lesson Objectives: • Define microbiology. • List the organisms included in the field of microbiology . • Discuss the role microorganisms play in the environment, the food industry and the medical field. • List the distinguishing characteristics of bacteria, fungi, algae, protozoa and viruses. • Describe how bacteria are named. • List the microorganisms that are classified as prokaryotes and eukaryotes.

  3. Microbiology The study of living organisms too small to be seen with the naked eye. Question: (with a partner) What event, discovery, or invention marked the start of Microbiology? Answer:________________________________

  4. Members • Bacteria • Fungi (yeasts and molds) • Protozoa • Algae • Viruses

  5. Prokaryote Cell

  6. Cellular Organization • Prokaryotes-Pre nucleus • Bacteria • Simple cells • Small • No membrane- bound nucleus. DNA is organized into one large circular strand (genome) and smaller circles (plasmids) • No membrane-bound internal structures (ribosomes present) • Cell division quick-Binary Fission

  7. Eucaryote

  8. Eukaryotes • True (good) nucleus • Membrane bound organelles • Includes fungi, algae, and protozoa, plants and animals • More structurally complex • Cell Division is by mitosis and meiosis

  9. Microbes and the Planet • First life on the earth • Prokaryotes (bacteria) appeared about 3.5 billion years ago • Eukaryotes ( all other microbes) arose 2 billion years ago • Ubiquitous • Adaptable to any niche that exists

  10. Microbes and the Planet • Essential for life • Photosynthesis • Microbes are responsible for over 70 % of Earth’s photosynthesis • First photosynthesis—did not produce oxygen! When oxygen was formed, an environment suitable for man and animals resulted. Earth’s environment is a result of microbial products soil water atmosphere

  11. Scope of Microbiology • Environmental • Most microbes are beneficial • Genetic engineering • Bioremediation • Food production • Symbionts—provide necessary processes to other organisms.

  12. Microorganisms and the Environment • Decomposition- recyclers of nutrients • Can breakdown complex organic compounds to simple compounds • Return CO2N2, and H20 to atmosphere and soil

  13. Scope • Food Microbiology Examples of food made possible by microbes:

  14. Microbes and Man Normal flora Pathogens Approximately what percentage of microbes are pathogens? Found in which parts of body?

  15. Medical Antibiotics fungus Why is there a clear zone here? Figure 1.5

  16. Classification and Nomenclature Names were originally based on visible characteristics of microbes: Microscopic appearance (Staphylococcus—”bunch of grapes,” Bacillus—”rod”) Discoverer of the organism or the disease (Salmonella: Daniel Salmon, Listeria: Joseph Lister) ??????????? (Pseudomonas: “false monad”)

  17. Taxonomy: Organizing, Classifying and Naming Living Things • Formal system originated by Carl von Linné (1701-1778) • Concerned with: • classification – orderly arrangement of organisms into groups • nomenclature – assigning names • identification – discovering and recording traits of organisms for placement into taxonomic schemes

  18. Woese System of Classification Carl Woese compared a macromolecule found in all cells (rRNA) and used the sequence of bases in this molecule as a basis of comparison in thousands of organisms.

  19. Why use ribosomal RNA • Every organism on the planet has rRNA, and it always has the same function. • The sequence of nucleotides (adenine, guanine, cytosine, uracil) in certain parts of rRNA undergo very little change throughout evolution. Therefore… • All members of a given species have the same rRNA sequence (in certain areas).

  20. Woese’s conclusion • Three major “domains” of living cells:BacteriaArchaeaEukarya • The first two are prokaryotes, the third is all eukaryotes • Bacteria and Archaea are as different from each other as each is from Eukarya

  21. Nomenclature • Binomial • Latinized • Genus-noun • Species-adjective • Genus (always capitalized) species (never capitalized) • Staphylococcus aureus • S. aureus • S. epidermidis

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