Microbe Classification

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Microbe Classification
2013-03-23 23:40:39
Microbe Classification

How microbes are classified
Show Answers:

  1. What is classification?
    The process of arranging organisms into groups or taxa. Tax include domain, phyla, classes, orders, families, genera and species.
  2. What is nomenclature?
    The system of principles, procedures and terms related to naming.
  3. What is the binomial system of nomenclature?
    The use of the genus and the specific epithet to determine the name of the species.
  4. What are the 2 domains of biological life?
    • Prokaryotic - Bacteria and Archea
    • Eukaryotic - Protozoa, amoebas , fungi, plants animals etc.
  5. What are 9 criteria that can be used to classify bacteria?
    • -Shape
    • -Stainability
    • -Colony features
    • -An/aerboic capacity
    • -Motility
    • -Nutrient requirements
    • -Pathogenicity (no known archea)
    • -Genetic composition
    • -Metabolic processes
  6. What are the 3 main shapes of bacteria?
    • Cocci - Spherical bacteria
    • Bacilli - Rod bacteria
    • Spirilla - Spiral bacteria
  7. What are 5 features that can be used to distinguish bacteria according to their colongy morphology?
    • -Size
    • -Colour
    • -Shape
    • -Elevation
    • -Appearance of colony edge
  8. What are the 5 categories of An/Aerobic bacteria?
    • -Obligate Aerobes
    • -Microaerophiles
    • -Facultative Anaerobes
    • -Aerotolerant anaerobes
    • -Obligate Anaerobes
  9. How is staining used to distinguish bacteria?
    Gram positive = thick peptidoglycan wall which stain adheres to. Shows BLUE/VIOLET

    Gram negative = thin peptidoglycan wall which loses its orignal stain, the PINK/RED counterstain thus shows up

    Mycobacteria = Cell wall contains waxes, acid fast process involving heat to soften waxes makes RED die adhere.
  10. What is the process of gram staining?
    • 1. Staining with the crystal violet stain
    • 2. Use of mordent to bind the stain
    • 3. Decolouration with alcohol or acetone
    • 4. Counterstaining, usually with safranin but sometimes carbol fuchsin for more intensity.
  11. What are obligate aerobes?
    Microbes that need oxygen in order to grow. They respirate and cannot live without oxygen levels approximating surface level air (20%).
  12. What are microaerophiles?
    Microbes that need oxygen to grow, but in less concentration than obligate anaerobes. They need around 5% concentration of oxygen and a higher concentration of carbon dioxide.
  13. What are facultative anaerobes?
    Microbes that are capable of synthesising ATP by using oxygen but can also use fermentation. Thus they are adaptive and can switch between being aerobic/anaerobic.
  14. What are aerotolerant anaerobes?
    They are anaerobic microbes that cannot use oxygen for their growth, but they do tolerate the presence of it, that is it does not poison them or severely inhibit growth.
  15. What are obligate anaerobes?
    Microbes that need the absence of oxygen to grow, some of these microbes are even killed by oxygen.
  16. What makes chlamydias, rickettsias and mycoplasmas unique?
    Chlamydias and rickettsias are obligate intracellular microbes; they must be inside of  a host cell in order to live.

    Mycoplasmas do not possess a cell wall, with the lack of peptidoglycan they can be very hard to eradicate.
  17. What are the 5 eukaryotic forms of microbes?
    • -Some fungi
    • -Some algae
    • -Protozoa
    • -Lichens
    • -Slime moulds
  18. What are algae?
    A very diverse group of eukaryotes that photosynthesise, they are similar to plants, but are considered to be simpler and lack some cell types of plants. Some algae are microbial.
  19. What are protozoa?
    Protozoa are a diverse group of microbial, mostly unicellular eukaryotes. They are considered to be more similar to animal cells than plant cells and are often motile.
  20. What are the 2 stages of protozoan life?
    Trophozyte stage - The active, motile, feeding and breeding stage.

    Cyst stage - The inactive, non-motile dormant/survival stage.
  21. What are the four categories of protozoa?
    (They are based on the way they move)
    Amoebazoas - The temporarily extend parts of their cell membranes into projections called pseudophilia to facilitate movement.

    Ciliates - Use hair like cilia on the surface of the cell to facilitate movement.

    Flagelletes - Use flagella to propel themselves.

    Sporozoa - Do not contain pseudophilia, cilia or flagella to transport themselves.
  22. What are fungi and where are they found?
    Fungi are a diverse group of eukaryotes containing yeasts, moulds and mushrooms. They can be saprophytic or parasitic and are found almost everywhere. Their cell walls contain chitin, rather than cellulose.
  23. What are yeasts and where are they found?
    Yeasts are a subgroup of fungi that are unicellular and ferment. They are found in soil, water and on the skin of fruits and vegetables.