Bmsc 210 Mid1 p1

  1. Microbiology revolves around two themes
    • 1. Understanding basic life processes
    • • Microbes are excellent models for understandingcellular processes in unicellular and multicellularorganisms
    • 2. Applying that knowledge to the benefit of humans
    • • Microbes play important roles in medicine,agriculture, and industry
  2. Properties of all cells
    • 1Compartmentalization and metabolism
    • 2Growth
    • 3Evolution
  3. Properties of some cells
    • 1Motility
    • 2Differentiation
    • 3Communication
  4. Transcription:
    DNA produces RNA
  5. Translation:
    RNA makes protein
  6. Metabolism:
    generation of precursors of macromolecules(sugars, amino acids, fatty acids, etc.)
  7. The Importance of Microorganisms
    • – Oldest form of life
    • – Largest mass of living material on Earth
    • – Carry out major processes for biogeochemical cycles
    • – Can live in places unsuitable for other organisms
    • – Other life forms require microbes to survive
  8. Diversity and abundances of microbes arecontrolled by:
    • -resources (nutrients)
    • -environmental conditions (e.g., temp, pH, O2)
  9. Last universal common ancestor (LUCA):
    common ancestral cell from which all cellsdescended
  10. Earth is ___ billion years old
  11. First cells appeared between___ and ____billion years ago
    3.8 ....3.9
  12. -Metabolisms were exclusively anaerobic until
    evolution of oxygen-producing phototrophs (cyanobacteria)
  13. The atmosphere was anoxic until ~__ billion years ago
    • 2
    • (anoxic:absence of oxygen)
  14. Life was exclusively microbial until ~__ billionyears ago
  15. Positive impacts of Microorganisms on Agriculture
    • – nitrogen-fixing bacteria
    • – cellulose(degrading microbes in the rumen)
    • – regeneration of nutrients in soil and water
  16. Negative impacts of Microorganisms on Agriculture
    – diseases in plants and animals
  17. Nitrogen fixation
    • -process by which nitrogen gas (N2-) in the atmosphere is converted into ammonia (NH3) and then nitrates.
    • -essentially for plants because nitrogen gas is not bioavailable
    • Image Upload 1
  18. Rumen bacteria
    • -microbes found in animals rumens
    • -digest cellulose into fatty acids for nutrition
    • -byproducts are methane (CH4) and carbon dioxide(CO2)
    • Image Upload 2
  19. Negative impacts of Microorganisms on Food
    -Food spoilage by microorganisms requiresspecialized preservation of many foods
  20. Positive impacts of Microorganisms on Food
    • Microbial transformations (typically fermentations)yield
    • – dairy products (e.g., cheeses, yogurt, buttermilk)
    • – other food products (e.g., sauerkraut, pickles,leavened breads, beer)
  21. Human uses for microorganisms
    • -Exploitation of microbes production of antibiotics, enzymes, and various chemicals
    • -Genetic engineering of microbes to generate products of value to humans, such as insulin(biotechnology) Pathways
  22. Robert Hooke
    (1635–1703): the first to describe microbes– Illustrated the fruiting(reproductive) structures of molds
  23. Antoni van Leeuwenhoek
    • (1632–1723): the first to describe bacteria
    • – Further progress required development of more powerful microscopes- Small lense, high resolution, permanent focus
  24. Ferdinand Cohn
    (1828–1898): founded the field of bacterial classification and discovered bacterial endospores
  25. Louis Pasteur (1822–1895)
    • -Discovered that living organisms discriminate between optical isomers
    • – Discovered that alcoholic fermentation was a biologically mediated process (originally thought tobe purely chemical)
    • – Disproved theory of spontaneous generation
    • - Led to the development of methods for controlling the growth of microorganisms (aseptic technique)
    • – Developed vaccines for anthrax, fowl cholera, and rabies
  26. Robert Koch (1843–1910)
    • – Demonstrated the link between microbes and infectious diseases
    •      • Identified causative agents of anthrax and tuberculosis
    • – Koch’s postulates
    • – Developed techniques (solid media-cut potatoe) for obtaining pure cultures of microbes, some still in existence today
    • – Awarded Nobel Prize for Physiology andMedicine in 1905
  27. Pure colony
    an entire colony grown from a single cell
  28. Kochs postulates
    Image Upload 3
  29. Martinus Beijerinck (1851–1931)
    • – Developed enrichment culture technique
    •  • Microbes isolated from natural samples in ahighly selective fashion by manipulatingnutrient and incubation conditions
    • – Example: nitrogen-fixing bacteria (Figure 1.21)
  30. Sergei Winogradsky (1856–1953)
    • and the Concept of Chemolithotrophy– Demonstrated that specific bacteria are linked to specific biogeochemical transformations (e.g., S & N cycles)– Proposed concept of chemolithotrophy
    •  • Oxidation of inorganic compounds linked to energy conservation
Card Set
Bmsc 210 Mid1 p1
Bmsc 210 Midterm 1