Week 1

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Week 1
2012-01-20 22:25:49
cell growth bacteria archaea

week 1 of biology 121
Show Answers:

  1. who discovered the cell?
    Anton van leeuwenhoek was the first to view the single celled "animalcules" in pond water (paramecium)
  2. Name the domains of Cellular life
  3. T/F: Prokaryotes do not have a nucleus.
  4. T/F: Eukaryotes do not have a nucleus.
  5. What is the size ratio of a prokaryotic cell to a eukaryotic cell?
    a)10 to 1
    b)100 to 1
    c)20 to 1
  6. What is the volume ratio between a prokaryotic cell and a eukaryotic cell?
    a)100 to 1
    b)200 to 1
    c)1000 to 1
    d)2000 to 1
  7. What organelle does a prokaryotic cell resembles in size?
    a) centrosome
    b) ribosome
    c) mitochondria
    d) vacuole
  8. T/F: Bacteria and Archaea are morphologically different.
    false. they are similar.
  9. What are the types of Bacterial cells?
    • 1)Gram positive
    • 2)Gram negative

    The difference is in the cell wall composition
  10. T/F: Every cell in the body has the exact same DNA and therefore can perform all the different functions of the body.
    False. The DNA is the same but the funtion is different for each specialized cell because certain genes are turned on(in use) while others are turned off.
  11. Provide a rationale to the statement that all cells have same DNA material
    At the time of fertilization there is a complete set of DNA present. (father+mother) therefore all the cells arising afterwords are through the process of mitosis which conserves the DNA material.
  12. What is a Gene?
    • A gene is a segment of DNA coding for a specific protein.
  13. What is the composition of cells after water is removed?
    • -50% proteins
    • -20% RNA/DNA
    • -10% Carbohydrates
    • -5% lipids and phospholipids
  14. Which statements are true about Bacteria?
    a)they can survive harsh temperatures
    b)they can survive harsh ph levels
    c)they easily adapt to new and extreme environments
    d)they divide via binary fusion
    ans: a,b
  15. T/F: Bacterian are seen in nature as unicellular orgasnisms
    False: multicellular bacterium e.g. Stigmatella aurantiaca
  16. What determines growth rate?
    • -Source of C,H,N,O,P,S and minor elements Mg2+ and Fe2+
    • -Specific organic nutrients (glucose,aminoacids)
    • -if needed Source of energy : from oxidation /redxn reactions or from light
  17. What other factors determine growth rate?
    • nutrient competition
    • water
    • temperature
    • ph level
  18. How does Adequate [ ] of substances affect cellular processes and limits cell size?
    • - Reactants need to collide and bind in a rxn
    • - high [ ] = high frequency of collisions
    • - as cell size increases #of molecules must increase
    • - if cell becomes 2x then [ ] need to be 8x
  19. How do the cells overcome this concentration problem?
    • By compartmentalizing cellular fxns they make areas of high [ ] where rxns can take place.
    • (i.e. mitochondria, chloroplast)
  20. How is cell size limited due to rates of diffusion?
    • - too big = hard to transport materials to "sites"
    • - diff size of molecules = diff diffusion rates (large vs small)
  21. How do cells overcome this limiting factor?
    • - the cells use special carrier proteins
    • - Cytoplasmic streaming (active mixing of cytoplasm)
  22. How is the size of a cell limited by the SA to V ratio?
    • - Volume = amount of nutrients imported and wastes exported
    • - Volume increases much faster compared to the SA when the size is increased
  23. How do cells overcome the SA to V ration barrier?
    - increase folding of membrane to increase SA (villi etc)
  24. What is the condition of a bacteria culture at point A?