Plasma Membrane & Cellular Transport

1. Plasma Membrane & Cellular Transport http://www.i-sup2008.org/images/venue_transport.jpg

2. Cell Transport A cell has to move food and wastes into and out of the cell. Materials must move through the plasma membrane which maintains homeostasis in the cell. food food food waste waste waste waste food

3. Cell Transport The Plasma Membrane surrounds the cell. How does it work?

4. Plasma Membrane Boundary between the cell and its environment • Allows nutrients into the cell • Removes wastes and excess materials • Maintains homeostasis: a stable internal environment

5. Plasma Membrane How does it work? • Selectively permeable: only allows some molecules in the cell, keeps others out http://media3.washingtonpost.com/wp-dyn/content/photo/2006/10/15/PH2006101500491.jpg

6. Plasma Membrane 2. Fluid Mosaic Model: membrane is flexible, made of many pieces working together Fluid Mosaic Molecules are able to move around within each layer of the membrane. Molecules moving around on surface create different patterns. http://www.youtube.com/watch?v=Qqsf_UJcfBc

7. Plasma Membrane 3. Phospholipid Bilayer: membrane is 2 layers, made of phospholipids with proteins mixed in http://www.utm.utoronto.ca/~w3bio315/lecture2.htm

8. Plasma Membrane Parts Phosphate heads – hydrophilic (like water), outside and inside membrane Fatty Acid Tails – hydrophobic (fear water), inside membrane, like OREO cream Cholesterol – prevents fats from sticking together, stabilize membrane Transport proteins – move molecules into and out of cell Identification proteins – outside cell, “nametag” Support proteins – inside cell for framework, “skeleton” Carbohydrates – serve as markers or “nametags”

9. Passive Transport NO ENERGY required, moves molecules from high concentration to low concentration 1. Diffusion - molecules move from an area of high concentration to low concentration http://iweb.tntech.edu/mcaprio/diffusion-animated.gif

10. Passive Transport – no energy required 2. Osmosis – diffusion of water molecules across a selectively permeable membrane http://schools.moe.edu.sg/chijsjc/Biology/Diffusion&osmosis/osmosis.gif

11. Solutions Isotonic solution – equal concentrations of solute (salt) inside and outside cell http://www.biologycorner.com/resources/isotonic.gif

12. Solutions Hypotonic solution – less solute in solution, more solute in cell, WATER FOLLOWS SALT, cells swell http://www.biologycorner.com/resources/hypotonic.gif

13. Solutions Hypertonic solution – more solute in solution, less solute in cell, WATER FOLLOWS SALT, cells shrink http://www.biologycorner.com/resources/hypertonic.gif

14. Osmosis in blood cells http://aryatiabdul.files.wordpress.com/2008/07/osmosis2.gif

15. Solutions – how transport affects animals and plants http://kentsimmons.uwinnipeg.ca/cm1504/Image130.gif

16. Transport in Plants Healthy plant cells are crisp due to TURGOR PRESSURE Wilted plant cells are flaccid due to lack of water

17. Passive Transport – no energy required 3. Facilitated Diffusion – movement of molecules from high concentration to low concentration with help of membrane transport proteins Low concentration High concentration http://www.biology.arizona.edu/CELL_BIO/problem_sets/membranes/graphics/CHANNEL.GIF

18. Active Transport Requires energy Moves molecules against concentration gradient Moves molecules from area of low concentration to area of high concentration Examples: gated channels, sodium/potassium pumps, endocytosis, exocytosis

19. Active Transport Endocytosis and Exocytosis http://media-2.web.britannica.com/eb-media/38/8038-004-A29C9C02.jpg