Card Set Information

2010-10-03 20:45:13
Chapter III

Unit Test I
Show Answers:

  1. What function do the Centrioles serve?
    • Centrioles give rise to cilia and flagella.
    • - only ciliated or flagellated cells have function centrioles-
  2. What does it mean if a molecule is Hydrophobic or Hydrophillic?
    • Hydrophobic - the molecule is not attracted to water's polarity
    • Hydrophillic - the molecule is attracted to water due to water's polarity
  3. What is important about cholesterol in relation to steroid hormones?
    It is the "basis" or precurser to steroid hormones
  4. What important property does choleserol give to the phospholipid bilayer?
    Cholesterol provides resilience against the bilayer tearing or bursting.
  5. What are the two major classifications of proteins found in the cell membrane?
    • Integral - passes through oth sides of the bilayer
    • Peripheral - only embedded into one side of the bilayer
  6. What are cell surface markers?
    Integral proteins that identify cell type and the origin orgnism of the cell. Unique to each genetic individual. Called glycoproteins due to the protein having a sugar-based portion attahed to it. MHC (Major Histocompatibility Complex) Antigens are and example.
  7. What are integrins and cadherins?
    • These are both types of attachment sites in cells.
    • integrins - attach to extracellular proteins
    • cadherins - join cells to other cells
    • - tight junctions - prevents any fluid from squeezing between the cells
    • - gap junctions - allow ions to flow between cells and coordinates contraction of the heart muscle
  8. What are the two types of channel proteins?
    • Leak
    • Gated
  9. How do leak channel proteins work?
    • These channel proteins are permanently open.
    • - substances that can fit through them are constantly passing through them -
  10. How do gated channel proteins work?
    • Gated proteins either open or close in response to stimuli.
    • - Voltage gated : electrical timuli causes opening or closing
    • - Chemically gated : some molecule or ion causes the gate to open when the molecule or ion binds to the protein
    • - Mechanically gated : some force or physical contact causes channel to open or close
    • - Light gated : Found in eye's rods and cones. Light causes channel to open or close.
  11. What are carrier proteins?
    • Carrier proteins change their shape due to some stimuli. Always integral proteins.
    • Involved in:
    • - Facilitated Diffusion (passive)
    • - Secondary Active Diffusion (Active;requires energy)
    • - Primary Active Diffusion (Active; requires energy)
  12. What is a ligand?
    • A ligand is a molecule or ion that bonds to a protein and cause a change in the protein.
    • - typically seen in carrier or receptor proteins -
  13. What is the name of the change that occurs when a ligand binds with a protein?
    Conformational Change
  14. What is a receptor protein?
    A protein that reacts to a ligand but does not move the ligand across the phospholipid bilayer
  15. What are membrane bound enzymes?
    Enzymes that are embedded in the bilayer
  16. What is diffusion?
    • The net movement of microscopic particles from an area of High particle concentration to an area of Low particle concentration.
    • -small non-polar molecules can diffuse through channels or bilayer itself
    • -large non-polar molecules can only go through the bilayer
  17. What is osmosis?
    The net movement of H2O molecules across a selectively permeable membrane from and area of Low solute concentration to an area of High solute concentration
  18. What is osmotic pressure?
    the amount of force or pressure required to prevent or stop osmosis
  19. What is the average body cell solution and what does that percentage mean?
    • Average body cell is 0.9% solute
    • - for every 100mL of solution, there is 0.9g or solute -
  20. What is cytolysis?
    Whaen a cell breaks or ruptures
  21. What is dynamic equilibrium?
    the point where net movement of a substance is no longer greater in any particular direction. Movement still occurs, thee is just no net movement
  22. What is a major difference etween diffusion vs. facilitated diffusion?
    • -Diffusion is any movement down a concentration gradient w/o assistance.
    • -Facilitated diffusion only happens across cell membranes as it needs carrier proteins to happen
  23. What are the three types of mediated transport mechanisms?
    • - Facilitated Diffusion
    • - Primary Active Transport
    • - Secondary Active Transport
  24. What is Facilitated Diffusion?
    • -Diffusion that occurs through an integral carrier protein.
    • -follows the concentration from area of high to low
    • -No ATP is required for facilitated diffusion to occur
  25. What is primary active transport?
    • -primary active transport utilizes integral carrier proteins
    • -it requires ATP as an energy source
    • -there are only four known primary active transport proteins
  26. What is an ATPase?
    An enzyme that hydrolyzes ATP to release energy that typically causes a conformational change in the enzyme
  27. What are the four primary active transport proteins, what do they do, where are they found?
    • - Na+,K+ ATPase (Sodium Potassium Pump) : Extremely important and found in all cells
    • - H+ ATPase : Found only in the plasma membrane of intercalated cells of the kidneys. Pumps H+ out of the cell and into the kidney tubules
    • - H+,K+ ATPase : Found onl in the plasma membrane of parietal cells of the stomach lining. Pumps H+ out of cells and into stomach lumen. Pumps K+ into cells from the stomach lumen.
    • - Ca2+ ATPase : found only in the membrane of the sarcoplasmic reticulum of muscle cells. Pumps Ca2+ into sarcoplasmic reticulum from cytoplasm.