Lipids, Membranes, and the First Cells

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Lipids, Membranes, and the First Cells
2010-03-20 00:55:51
Test 2

BIOL 203
Show Answers:

  1. What kind of diffusion do membrane proteins perform?
    Facilitated diffusion and Active Trasport
  2. What are lipids?
    Carbon containing compounds that are largely non-polar and hydrophobic
  3. What are hydrocarbons?
    molecules that contain only hydrogen and carbon
  4. What is the major hydrocarbon component in a lipid?
    Fatty Acid
  5. What is a fatty acid?
    Hydrocarbon chain bonded to a carboxyl group.
  6. Three types of lipids found in cells?


  7. What is a Fat?
    three fatty acids linked to a glycerol
  8. What is a steroid?
    family of lipids distinguished by a four-ring structure
  9. What is a Phospholipid?
    Glycerol linked to a phosphate group and either 2 chains of isoprene or fatty acids
  10. What does amphipathic mean?
    Containing both hydrophobic and hydrophillic parts
  11. How do Phosopholipid bilayers form (lipid bilayers)?
    Two sheets of phospholipid molecules align where the non-polar tails face each other and the polar head are facing the surrounding solution.

    They form spontaneously with no outside input of energy
  12. How do phosholipid bilayers have selective permeability?
    small and nonpolar molecules move across the bilayer quickly

    Charged or large polar substances move across slowly, if at all
  13. Unsaturated Lipid?
    has a double bond between two carbons in a hydrocarbon chain
  14. Saturated lipids
    hydrocarbons without double bonds
  15. Membrane fluidity decreases with temperature beacause...
    molecules in the bilayer move more slowly
  16. Decreased membrane fluidity causes...
    decreases permeability
  17. what is a solute?
    Small ions and molecules in a solution
  18. Hypertonic solution?
    Solute concentration higher outside the cell, so water moves out of the cell
  19. Hypotonic solution?
    Solute concentration higher inside the cell, so water moves into the cell
  20. Isotonic solution?
    Solute concentration are equal inside and outside the cell.
  21. Integral proteins that span the membrane are?
    Transmembrane proteins
  22. Function of transmembrane proteins?
    transport of selected ions and molecules across the plasma membrane
  23. Transmembrane proteins that transport molecules are called?
    Transport proteins
  24. Three types of transport proteins?

    Carrier Proteins

  25. Channel proteins are responsible for what type of diffusion
    Facilitated diffusion
  26. What is facilitated diffusion?
    The passive transport (no energy used) of substances that would not otherwise cross the membrane
  27. Two methods facilitated diffusion can occur?

    Carrier Proteins
  28. Active Transport
    Transport of molecules or ions against a electrochemical gradient - requires ATP.
  29. What do pumps create?
    A chemical and electrical gradient across the membrane
  30. Three mechanisms of membrane transport?

    Facilitated diffusion

    Active Transport