Bio 1215 LAB1a

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Bio 1215 LAB1a
2012-01-18 13:47:08
Bio 1215

The domains of life: Archaea and Bacteria
Show Answers:

  1. Compare the amount of species identified and the number the planet actually has
    Over 1.5 million species have been identified but total number of spcies on this planet is probably close to 30 million
  2. Prokaryotic organisms used to be known also as?
  3. Define Prokaryotic Organisms
    The prokaryotes (or) are a group of organisms that lack a cell nucleus (= karyon), or any other membrane-bound organelles.
  4. Define eukaryotes organisms
    A single-celled or multicellular organism whose cells contain a distinct membrane-bound nucleus
  5. How did the creation os a new taxonomic category, (the domain) come to be?
    Because biologists realized that a small group of prokaryotic organisms had as much in common with eukaryotes as they had with true bacteria, and didn't really belong to either group.
  6. What is the difference between domains and kingdoms?
    Domains are larger and more inclusive than kingdoms
  7. What three domains are all organisms currently placed in?
    The Archaea(formerly archebacteria), the Bacteria (formerly eubacteria) and the Eukarya (all the eukaryotic groups)
  8. What subdivision is Kingdoms divided into?
    Phyla (Phylum = singular)
  9. What subdivisions are phyla divided into?
    Class, Order, Family Genus, and species
  10. What is the order of the (groupings)domains of life?(8)
    Drunk King Phil Came Over For Great Scotch

    • 1. Domain
    • 2. Kingdom
    • 3. Phylum
    • 4. Class
    • 5. Order
    • 6. Family
    • 7. Genus
    • 8. species
  11. What are two things you should take note of when naming genus and species?
    Species name is NOT capitalized and the genus and species are underlined OR italicized.


    • Human
    • Genus: Homo
    • species: sapiens
  12. Compare and contrast Archaea and Bacteria
    • Similarities
    • 1. No nuclear envelope, membrane-enclosed organelles
    • 2. Both have circular chromosome

    • Differences
    • 1. Bacteria has Peptidoglycan in cell wall
    • 2. Bacteria has all unbranched hydrocarbons in membrane lipids
    • 3. Bacteria has only one kind of RNA polymerase
    • 4. Bacteria growth is inhibited by antibiotics
    • 5. Bacteria has no histones associated with DNA
    • 6. Bacteria does not grow at temp > 100C

    • Domain Bacteria:
    • 1. Cell wall contains peptidoglycan.
    • 2. DNA differs greatly from the DNA of members of the Eukarya Domain.
    • 3. Heterotroph.
    • 4. DNA has histones.
    • 5. Growth inhibited if it encounters antibiotics such as Streptomycin.
    • 6. One kind of RNA.
    • 7. Unbranched hydrocarbon
    • .8. Cannot live in environments with temperatures above 100 degrees Celcius.

    • Domain Archaea.
    • 1. Cell wall lacks peptidoglycan.
    • 2. DNA much closer to Eukarya than Bacteria.
    • 3. Autotroph.
    • 4. DNA lack histones.
    • 5. Growth not inhibited by antibiotics.
    • 6. Several kinds of RNA.
    • 7. Some have unusual lipids, and branched hydrocarbon.
    • 8. Can live in extreme temperatures.
  13. Compare and Contrast Archaea and Eukarya
    • Similarities:
    • 1. No Peptidoglycan in cell wall
    • 2. Have Several Kinds of RNA polymerase
    • 3. Both have Methionine as an initiator amino acid for protein synthesis
    • 4. Growth not inhibited by antibiotics

    • Difference
    • 1. Archaea has nuclear envelope and membrane-enclosed organelles, circular chromosome
    • 2. Eukarya have unbrached hydrocarbons in lipids
    • 3. Eukarya not able to grow at temp greater than 100C
  14. What is cell morphology?
    It is the cell's shape and the basic but universal way to classify bacterial diversity.
  15. What are the three morphology of bacteria and their scientific names?
    Round bacteria are called cocci (coccus = singular), rod-shaped abcteria are bacilli (bacillus = singular), and long, spirally coiled forms are spirilla (spirillum = singular)
  16. How was cyanbacteria discovered?
    It used to be called blue green algae but after transmission electron microscope was invented, the blue green algae was discovered to be prokaryotes. SO therefore, cyanobacteria.
  17. What four ways makes a cyanobacteria unusual?
    • 1. They are much larger than "traditional" bacteria and can be seen easily with 40x lens
    • 2. They are multicellular
    • 3. They are photosynthetic
    • 4. Most of them grow in filaments
  18. What is a filament?
    A filament is a chain of cells that makes up a single organism
  19. Give two types(examples) of cyanobacteria
    • 1. nostoc
    • 2. oscillatoria
  20. What two groups is bacteria classifed into? and describe them.
    They are based into two groups based on the structure of their cell wall

    1. Gram positive bacteria - a very thick layer of peptidogycan surrounds the cell membrane

    2. Gram negative bacteria have a more complex cell wall - a thin layer of peptidogycan is sandwichd between an inner and outer membrane
  21. What are two ways gram stain is used for?
    • 1. basic research tool
    • 2. first step in identifying pathogenic bacteria and determining an appropriate course of treatment for infections
  22. Is E.coli gram positive or negative?
    Gram negative
  23. How do you know Ecoli was a gram negative and S.epidermidis was a gram positive doing the lab?
    The gram positive turned purple with both decolorizer and safranin.

    The gram negative was colourless with the decolorizer and pink with the safranin.
  24. Why is the decolorizer used in gram staining and how does it work?
    Since the decolorizer contains alcohol, which partially dissolves the lipids of the outer bacterial membrane.

    The purple stain was squeezed out through the pores in the thin layer of peptidoglycan in the Gram negative cell wall, but leaving the cell colourless.

    But since the Gram positive cells peptidoglycan layer is so thick, the purple stain is unable to escape.
  25. What two things you have to be careful about when using oil immersion?
    1. Do not touch the dropper to the slide or it will damage the specimen on the slide and contaminate the oil in the bottle.

    2. Once you have used oil on a slide, you CANNOT go back to 40x again, or you will get oil on the 40x lens.
  26. Whats the Morphology of E.coli and S.epidermidis?
    E.coli = Bacilli (Rod shaped)

    S.epidermidis = cocci (round)
  27. What is peptidoglycan?
    AKA. murein, a polymer consisting of sugars and amino acids taht form a mesh-like layer outsdie the plasma membrane of the bacteria, forming the cell wall
  28. What would happen to the bacteria if decolorizer was added for 30 seconds instead of 3 seconds?
    • the crystal violet stain will be removed from both Gram-positive and
    • negative cells if the decolorizing agent is left on too long
  29. Why is it necessary to add a counterstain?
    To give gram(-) a colour so you can see different parts of the organism under a microscope
  30. Microoganisms are said to be ubiquitous. Define ubiquitous
    They are found everywhere.
  31. What is a bacterial colony?
    A group or cluster of bacteria derived from one common bacteria.
  32. What are different bacterial morphology shapes?
    • ~bacillus (pl. bacilli) = rod-shaped
    • ~ coccus (pl. cocci sounds like cox-eye) = spherical
    • ~ spirillum (pl. spirilla) = spiral

    • Some bacteria have more unusual shapes:
    • ~ coccobacilli = elongated coccal form
    • ~ filamentous = bacilli that occur in long threads
    • ~ vibrios = short, slightly curved rods
    • ~ fusiform = bacilli with tapered ends
  33. Cocci divide on one or more planes producing cells in pairs, chains, packets and clusters. What are the scientific names for these?
    • Cocci divide on one or more planes, producing cells in:
    • ~ pairs (diplococci)
    • ~ chains (streptococci)
    • ~ packets (sarcinae)
    • ~ clusters (staphylococci)
  34. What are some characteristics of different colonies that can be helpful in identifcation of species
    Colony morphology is a way scientists can identify bacteria. There are a few basic characteristics of colony morphology that are typically evaluated.

    1. Form - What is the basic shape of the colony? For example, circular, filamentous, etc.

    2. Elevation - What is the cross-sectional shape of the colony? To see this, turn the Petri dish on end.

    3. Margin - What is the magnified shape of the edge of the colony?

    4.Surface - How does the surface of the colony appear? For example, smooth, glistening, rough, dull (opposite of glistening), rugose (wrinkled), etc.

    • 5. Opacity - Is the colony transparent (clear),
    • opaque, translucent (almost clear, but distorted vision, like looking through frosted glass), iridescent (changing colors in reflected light),
    • etc.

    6. Chromogenesis (pigmentation) - For example, white, buff, red, purple, etc
  35. What are biochemical tests ued for?
    These tests distinguish between bacteria on the basis of what they can metabolize, and what waste products are produced.
  36. why is bacterial identification not based simply on morphology? as it is with most other organisms?
    Because many bacteria have similar shapes yet have different functions.
  37. What are some diseases caused by bacteria?
    • Bubonic Plague
    • Cholera
    • Tuberculosis
    • Salmonellosis
    • Tetanus
  38. What are 4 ways bacteria are beneficial?
    • 1. important in the processes of decay and nutrient recycling in our environment
    • 2. important in photosynthesis, which provides organic nutrients for the biosphere
    • 3. nitrogen fixation
    • 4. food industry
  39. What is nitrogen fixation and why is it important?
    Nitrogen Fixation, a process of combining atmospheric nitrogen with other elements to form useful compounds.

    Nitrogen is essential to living things and, because most organisms cannot use nitrogen that is not combined with other elements, nitrogen fixation is important to the continuation of life on earth.
  40. What two categories of food products require bacteria in their manufacture?
    • 1. Dairy
    • 2. Preservative(canned foods), Processed foods
  41. What two ways are bacteria used commercially?
    • 1. To produce pesticides
    • 2. For antibiotics
  42. What are food supplements used for?
    TO get helpful bacteria back into intestines after they are killed by braod-spectrun antibiotics
  43. What is the main resident of bacteria on skin?