Cell transport.ppt n


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Cell transport.ppt n

  1. 1. Cell Boundaries  Every living cell exists in liquid environment.  There is liquid on the inside and outside of a cell.  One of the most important functions of the cell membrane is to regulate the movement of molecules from one side membrane to the other side.
  2. 2. Semi-Permeable Membrane  Smaller molecules can pass through.  Larger molecules cannot.
  3. 3. Diffusion  Movement particles from high to low concentration.  Diffusion will occur until equlibrium is reached.  This process does NOT require cellular energy (ATP).
  4. 4. Osmosis  Diffusion of water across cell membrane from high to low concentration.  Water molecules can very easily pass through cell membranes, because they are small.
  5. 5. Solution Concentrations  The cytoplasm of a cell is solution of many substances dissolved in water.  A solution is mixture of two or more substances.  The substances dissolved in a solution are called solutes.  The concentration of solution refers to amount of solute dissolved in liquid (solvent).
  6. 6. Solution Solute Solvent
  7. 7. Environment of the Cell  The solution concentration outside the cell will determine the direction water moves across the cell membrane.  The terms hypotonic, hypertonic, and isotonic are ADJECTIVES! They describe the environment of the cell!!!
  8. 8. Hypertonic Environments  Low concentration of water/High concentration solutes outside cell.  Water diffuses out of the cell and cell shrinks.
  9. 9. Hypotonic Environments  High concentration of water/Low concentration solutes outside cell.  Cells swell with water and may explode.
  10. 10. Isotonic Environment  Equal concentration of water/solutes inside and outside the cell.  Water will move equally in/out cell.
  11. 11. 96% Water, 4% salt 98% Water, 2% Salt 97% Water, 3% Salt 95% Water, 5% Salt 98% Water, 2% Salt 98% Water, 2% Salt
  12. 12. Osmotic Pressure  Water pressure that builds up inside a cell due to a hypotonic environment.  If pressure is too high, what could happen?  Osmotic pressure in plants = turgor pressure.  Cell Wall helps to with stand turgor pressure.
  13. 13. Plasmolysis- loss of water or “wilting” in plants
  14. 14. Facilitated Diffusion  Some particles are too large to pass through the membrane.  They need help from channel proteins.  This process does NOT require energy! Glucose Channel Protein
  15. 15. Passive Transport  Particles moving from high to low concentration.  Doesn’t require energy.
  16. 16. Active Transport  Occasionally, particles need to move “against the concentration gradient.”  Particles moving from low to high concentration.  Requires energy (ATP).
  17. 17. Endocytosis  Type of active transport.  Process of taking in large amounts of food or liquid by means of active transport. 1. Phagocytosis (cell eating) – Taking in large clumps of food. 2. Pinocytosis (cell drinking) – Taking in large amounts of liquid.
  18. 18. Exocytosis  Type of active transport.  Forcing contents out of the cell.  Method of removing large amounts of waste from cell.