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Cells and their environment

Cells and their environment. DOES NOT require ATP energy Occurs spontaneously From area of higher concentration to area of lower concentration With concentration gradient. DOES require ATP energy From area of lower concentration to area of higher concentration

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Cells and their environment

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  1. Cells and their environment

  2. DOES NOT require ATP energy Occurs spontaneously From area of higher concentration to area of lower concentration With concentration gradient DOES require ATP energy From area of lower concentration to area of higher concentration Against concentration gradient Passive and Active Transport

  3. Passive Transport • http://www.vivo.colostate.edu/hbooks/cmb/cells/pmemb/passive.html • http://biology.about.com/library/weekly/aa053101a.htm

  4. Lets take a look at the cell membrane: • The cell membrane is selectively permiable • made up of a phospholipid bilayer. • phosphate group and 2 fatty acids.

  5. Cell Membrane • These phospholipids are arranged in a double layer with nonpolar tails to the inside. • Water on the inside and outside of the cell repels the tails. • This bilayer is fluid.

  6. Lipid bilayer

  7. Cell Membrane

  8. Cell membrane

  9. Cell Membrane • Proteins are embedded in the lipid bilayer • proteins recognize and bind to certain substances • proteins move the substance through the membrane into the cell. • http://www.stolaf.edu/people/giannini/biological%20anamations.html • (Fluid bilayer)

  10. Diffusion • Diffusion is simple passive transport • Only occurs when there is a concentration gradient. • Equilibrium is the eventual result. • Many substances such as molecules and ions enter or leave cells by diffusing across the cell membrane. • http://www.northland.cc.mn.us/biology/Biology1111/animations/transport1.html • http://www.stolaf.edu/people/giannini/biological%20anamations.html • (diffusion)

  11. Diffusion

  12. Diffusion

  13. Diffusion • Factors that influence how fast diffusion takes place are: • Temperature – warmer molecules move faster • Size – smaller molecules move more easily • Concentration gradient – the more molecules or ions on one side, the more they want to get to the other side

  14. Lets see an example of this!

  15. Osmosis • This is a special kind of diffusion • This is movement of WATER ONLY • Water always wants to dilute, so it will move towards the side with more solutes

  16. Osmosis • http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/diffus.html • http://www.bbc.co.uk/education/asguru/biology/01cellbiology/05pathways/10osmosis/index.shtml • http://www.stolaf.edu/people/giannini/biological%20anamations.html • http://www.northland.cc.mn.us/biology/Biology1111/animations/transport1.html

  17. Osmosis • There are three possible directions for the movement of water. • Water moves out: hypertonic solution-causes the cell to shrink • Water moves in: hypotonic solution-causes cell to swell (possibly burst) • No Net water movement: isotonic solution: no change because the same amount is moving in as moving out.

  18. Osmosis http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBooktransp.html http://www.tvdsb.on.ca/westmin/science/sbi3a1/Cells/Osmosis.htm

  19. Osmosis

  20. Osmosis

  21. Diffusion through Ion Channels • An ion channel is a transport protein with a polar pore. Ions can pass through these. • http://www.stolaf.edu/people/giannini/biological%20anamations.html • Gates

  22. Facilitated Diffusion • This is still a passive form of transport. • No ATP energy is needed • Big molecules must go through transport proteins • Still move from areas of high concentration to low concentration

  23. Facilitated diffusion • http://www.northland.cc.mn.us/biology/Biology1111/animations/transport1.html • http://www.bbc.co.uk/education/asguru/biology/01cellbiology/05pathways/07passivefacilitated/index.shtml

  24. Active Transport • The cell must use ATP energy to get the molecules moved • Against the concentration gradient • The cell uses proteins that serve as pumps or channels to move the large molecules • Phagocytosis and Pinocytosis are examples

  25. Example of active transport • Sodium/Potassium pump with glucose symport • This is how you get glucose into your bloodstream after you eat • Animation

  26. Exocytosis • Particles are expelled from a cell Active Transport

  27. Phagocytosis- Large particles are engulfed by the cell Pinocytosis Small particles and liquids are engulfed by the cell Types of Endocytosis Active Transport

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