Cellular Transport

1. Cellular Transport On the following slides, the blue sections highlight the main points; summarize the slides for your notes. Underlined words = vocabulary!

2. Plasma MembraneAKA Cell Membrane Video http://droualb.faculty.mjc.edu/images/Anatomy/Cytology/FG02_05.jpg

3. http://www.theresedesjardinstudio.com/images-art-paintings-prints/Dons-images-graphics-photo/8MOSAIC.BIRD.OF.PARADISE-1A.jpghttp://www.theresedesjardinstudio.com/images-art-paintings-prints/Dons-images-graphics-photo/8MOSAIC.BIRD.OF.PARADISE-1A.jpg

4. Fluid Mosaic Model • Plasma membranes are commonly described as a fluid mosaic model; it is made of various molecules in a complicated phospholipid bilayer. • The plasma membrane is fluid, embedded with: • Proteins are used in transport • Cholesterol stabilizes the phospholipids • Carbohydrate chainsare markers, think “ID” tags

6. What is a concentration gradient? • Cells have to move things through membranes on a regular basis (food, water, waste, etc.). • The concentration gradientmeasures the amount of solutes in the fluid within and out of a cell Simulation http://cnx.org/resources/160ffab563fb667fb2ab5475bde02fb1/Figure_03_05_01.jpg

7. What is diffusion? • Diffusion is the movement of particles from a high concentration to a lower concentration to reachequilibrium (relatively the same or equal on all sides). • Facilitated diffusion is the process by which cells uses channel or carrier proteins imbedded in the plasma membrane as “doorways”. http://www.okc.cc.ok.us/biologylabs/Images/Cells_Membranes/diffusion.gif

8. What is osmosis? • Water is one of the most important nutrient that cells need in order to function. • Osmosis is the diffusion of waterthrough aselectively permeable (to permeate is to pass through) membrane and is controlled by the concentration of solutes in a cell’s environment. • Water will move easily, until the concentration is relatively equal on both sides of the cell membrane. Animation http://www.okc.cc.ok.us/biologylabs/Images/Cells_Membranes/osmosis.gif

9. Passive vs Active Transport • Diffusion and osmosis are processes within the cell that occur naturally, without the need for energy; considered passive transport. • Active transport is when cellsuses energy to move moleculesagainst the concentration gradient . • Carrier proteins act as “doorways” to move molecules and substances in and out of the cell from a low concentration to a high concentration. Video http://www.daviddarling.info/images/active_transport.jpg

10. Label: • High vs low concentration for each of the three scenarios • Diffusion • Facilitated diffusion • Active transport http://iws.collin.edu/biopage/faculty/mcculloch/1406/outlines/chapter%208/8-14.jpg

11. Knowledge Check • Take a deep breath! • How does oxygen get into your blood stream? How does it “diffuse”? • List your thoughts on the above question. Your answer must include:: • Where is oxygen MOST concentrated? • Where is oxygen LEAST concentrated? • Where will the O2 diffuse? Why? http://static.howstuffworks.com/gif/artificial-blood-8.jpg

12. Solutions and Cells • Hypotonic solution has a higher solute concentration inside the cell, so water will travel in to the cell (grow). • An isotonic solution (or “same strength”) is one where the concentration inside the cell matches the outside of the cell– there is equitable movement in and out. • Hypertonic solution has a higher solute concentration outside the cell, so water will travel out and it will shrink. http://biology.unm.edu/ccouncil/Biology_124/Images/tonicity1.jpeg

13. Sketch the graphics (be sure to include the H2O arrows!!!) Hyp”O”tonic – The cell gr”O”ws! Hype”R”tonic – The cell sh”R”inks! I”S”otonic = “S”ame! http://2.bp.blogspot.com/_10M5kCPMTYM/S-1kTAlmmrI/AAAAAAAAABc/Duc-LSzYgyU/s1600/Bio+hypotonic,+Isotonic,+Hypertonic.gif

14. Knowledge Check • Examine the diagram to the right. • Turn to your neighbor and answer the following questions: : • Where is water MOST concentrated in the top cell? • Where is water MOST concentrated in the bottom cell? • How will the cells change in the next as a result of the above? "Osmosis, cellular process of." Experiment Central. U*X*L, 2010. Science In Context. Web. 26 Sept. 2013.

15. What is phagocytosis? • Phagocytosis: the process when cells move shift the cytoplasm to surround a substance; means “cell eating” • Endocytosis = cell surrounds and takes in material • Exocytosis = cell expels wastes • Video1Video 2 http://static.howstuffworks.com/gif/artificial-blood-8.jpg

16. Limitations to Cell Size http://cnx.org/content/m44406/latest/Figure_04_02_02.jpg • In order for cells to diffuse materials easily in and out of their membranes, their size has to remain relatively small. • Diffusion - if cells are too large, it would take entirely too long for the materials to diffuse andreach their destinations.

17. Size Limitations Cont. • Proteins - The nucleus within eukaryotic cells carries DNA, instructions to make proteins; these proteins are needed throughout the cell (in almost all organelles) and for important functions. • The cell must stay small because proteins could not be made quickly enough to meet the demands for a large cell. http://2.bp.blogspot.com/_hhUdKwzDmA4/S7dXzoiCGiI/AAAAAAAAAhM/XiFyUjna6NQ/s1600/nucleic+acid.jpg

18. Size Limitations Cont. • Surface Area - As cells increase in size, the volume within them increases as well (the surface area to volume ratio). • As the volume increases, the need for materials is much greater than the surface area available to diffuse oxygen, nutrients, and expel wastes. • Cells must, therefore, remain small. http://highered.mcgraw-hill.com/sites/dl/free/0078757134/383917/bz.gif