BIO 110 CHAP 5.txt

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BIO 110 CHAP 5.txt
2012-10-19 09:53:25

BIO 110 CHAP 5
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  1. Fluid Mosaic Model
    • Cell membrane is mosaic, a mixed composition of mostly phospholipids. The fluid part of the model refers to the behavior of phospholipids in membranes.
    • The phospholipids drift sideways, spin on their axis and their tails wiggle.
  2. Differences in Membrane Composition
    • The difference reflect their functions in the cell
    • The two surfaces of the bilayer are different
    • Different kinds of cells have different kinds of membrane phospholipids
  3. Difference in Fluidity
    • While some proteins stay put locked in place by the cytoskeleton (those clustered as rigid pores), most proteins in bacterial and eukaryotic cell membranes drift around very quickly
    • Archaeans do not build their phospholipids with fatty acids and their bilayers are more rigid.
  4. Two categories of membrane proteins
    • Integral membrane proteins – permanently attached to a lipid bilayer
    • Peripheral membrane proteins temporarily attach to one of the bilayer’s surfaces by way of interactions with lipids or other proteins
  5. Types of Membrane Proteins
    • Adhesion Protein
    • Enzyme
    • Receptor Protein
    • Recognition Protein
    • Passive Transporter
    • Active Transporter
  6. Adhesion Protein
    • Function – attachment of cells to one another and to extracellular matrix
    • Occurs only on plasma membranes
    • Attachment – Integral
    • Examples:
    • -Integrins receptors that mediate cell attachment, migration, differentiation, division and survival
    • -Cadherins part of adhering junctions between cells
    • -Selections bind glycoproteins on the surface o cells that function in immunity
  7. Enzyme
    • Function - Speeds a specific reaction
    • Attachment – Integral or peripheral
    • Example:
    • Monoamine oxidase catalyzes a hydrolysis reaction that removes an ammonia group from amino acids.
  8. Receptor Protein
    • Function - Binding signaling molecules (receives signals)
    • Binding causes a change in the cell activity
    • Attachment – Integral or peripheral
    • Example:
    • B cell – Protein made only by white blood cells vital for immune response
  9. Recognition Protein
    • Function – identifier of cell type, individual, or species
    • Attachment – Integral
    • Example:
    • MHC molecule allows white blood cells to identify a cell as nonself or self to trigger immune response.
  10. Passive Transporter
    • Function – transport of molecules
    • Does not require energy
    • Attachment - Integral
    • Examples:
    • Glucose transporter
    • Aquaporin – open channel water transporter
  11. Active Transporter
    • Function – transport of molecules
    • Uses energy to pump substances across the membrane
    • Attachment – Integral
    • Examples:
    • Calcium pump – Uses ATP to pump calcium ions across a membrane
    • ATP synthase – Uses ATP to pump hydrogen ions across a membrane
  12. Mechanisms of membrane transport
    • Diffusion
    • Osmosis
    • Passive Transport (facilitated diffusion)
    • Active Transport
    • Vesicular Transport (endocytosis/exocytosis)
  13. Diffusion
    • The movement of particles from area of high concentration to an area of low concentration
    • Spontaneous – Happens in nature (needs not assistance)
    • Gas and water and small ions
    • Continues until equilibrium
  14. Passive Transport
    • The movement of particles from area of high concentration to an area of low concentration with the assistance of a protein
    • Channels (no interactions) or gates (interact open and close)
  15. Active Transport
    The movement of particles from low to high concentration with the assistance of protein and energy (ATP)
  16. Co-transporter
    Moves two substances at the same time nearly all of the cells in your body have these pumps
  17. Vesicular Transport
    • Uses vesicles to transport items
    • Exocytosis vesicles transport items to the PM fuses to expels the content of the Vesticle from the cell
    • Endocytosis (Bulk Flow / Receptor)
  18. Gradient
    Nature move and separation from high to low
  19. Osmosis
    Name for the movement of water
  20. Tonicity
    Relative concentration of solutes in two fluids that are separated by a selectively permeable membrane
  21. Terms of Tonicity
    • Hypotonic
    • Hypertonic
    • Isotonic
  22. Hypotonic
    Fluid with a lower concentration of solutes in comparison to another
  23. Hypertonic
    Fluid with a higher concentration of solutes in comparison to another
  24. Isotonic
    Fluids that has the same over all concentration of solute
  25. Water movement
    Water always move toward the higher concentration of solute
  26. Turgor
    Pressure that fluid exerts on cell wall due to swelling from water in a hypotonic situation
  27. Energy
    The capacity to do work
  28. First Law of Thermal Dynamics
    Energy is neither created nor destroyed.
  29. Second Law of Thermal Dynamics
    The tendency for entropy to increase
  30. Entropy
    Measure of how much the energy of a particular system has become dispersed
  31. Reactants -> products
  32. Law of conservation of mass
    Equal amount of mass on both sides of a reaction
  33. Subscript and Coefficient
    • – subscript denotes number of atoms
    • - Coefficient denotes the number of molecules
  34. Endergonic reaction
    Less free energy in the reactants than the products
  35. Exergonic reaction
    More free energy in the reactants that the products
  36. Free energy
    Amount of energy that is available to do work
  37. Activation energy
    The minimum amount of energy required to get a reaction started
  38. Enzymes
    Catalysts that speed up reactions
  39. Active site
  40. Transition state
    When substrates reach their breaking point and the reaction continues to product
  41. Lock and Key
    Substrate and enzyme come together and fit exactly (old model)
  42. Induced fit model
    The bonding of the enzyme and substrates improves the fit of the actives site and the substrate over time
  43. Metabolism
    Activities work in an organized manner
  44. Metabolic pathway
    • Liner
    • Cyclic
    • Branched
  45. Intermediates
    Products from a substrate enzyme reaction that go to other reactions.