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Passive Transport What can move into and out of cells?

Cell Membrane and Membrane Transport. Passive Transport What can move into and out of cells? Active Transport How do cells maintain homeostasis? http://www.northland.cc.mn.us/biology/Biology1111/animations/transport1.html. Warm-up: Write answers in spaces.

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Passive Transport What can move into and out of cells?

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  1. Cell Membrane and Membrane Transport Passive Transport What can move into and out of cells? Active Transport How do cells maintain homeostasis? http://www.northland.cc.mn.us/biology/Biology1111/animations/transport1.html

  2. Warm-up: Write answers in spaces. • Why is it necessary for cells to control what enters and leaves them?________________ ____________________________________ • Does passive transport take energy? ______ • Give one of the diffusion examples discussed last class.____________________________ • Explain what a concentration gradient is. ____________________________________ • Does diffusion involve going up or down a concentration gradient? _________________

  3. The Cell Membrane – a selectively permeable phospholipid bilayer with embedded proteins

  4. Passive TransportWhat can move into and out of cells? • Diffusion is Caused by the Random Movement of Particles • random motion and concentration causes… • movement of substances from an area of higher concentration to an area of lower concentration

  5. How does temperature affect the rate of diffusion? As temperature increases, the rate of diffusion _____________ .

  6. Concentration Gradient Type of transport?

  7. Passive Transport = Diffusion (and Osmosis!) • Movement of substances across a semi-permeable membrane from high to low concentration ** movement is down a concentration gradient example: clothes falling out of a packed closet your example:_______________ Does passive transport take energy? _____

  8. Water Diffuses into and out of Cells by Osmosis Osmosis – the diffusion of water through a selectively permeable membrane Does this take energy? _____ because we are talking about ________ transport

  9. red blood cells (animal)

  10. onion cells (plant)

  11. Osmosis of red onion cells Normal cells in tap water ______________ salt water is added… Salt water is _________________ compared to the red onion cells. __________________

  12. Did you know? H2O On humid days, wooden drawers in dressers absorb water from the air because of osmosis.

  13. more ways of passive transport… • Proteins Help Some Substances Cross the Cell Membrane • Diffusion though ion channels • A doughnut shaped protein with a polar hole • pulls ions through cell membrane like a magnet < Ion channel… inside is polar Phospholipid bilayer Cystic Fibrosis Website: http://www.dwmtech.com/Medical/cysticfibrosis.htm

  14. more ways of passive transport… • Facilitated diffusion • Uses carrier proteins to transport specific substances into or out of the cell

  15. Active TransportHow do cells maintain homeostasis? • Movement of substances across a semi-permeable membrane from low to high concentration ** upa concentration gradient ex: stuffing clothes into a closet to clean up your room your example:_______________________ Does this take energy? ________

  16. Sodium-Potassium Pump purpose: enables nerves and muscles cells to send electro-chemical signals http://www.brookscole.com/chemistry_d/templates/student_resources/shared_resources/animations/ion_pump/ionpump.html

  17. the sodium-potassium pump... • You may noticed every time the sodium-potassium pump operates, it pumps 2 K+ in and 3 Na+ out.  That is not an even exchange, right? • By pumping more positive charges out than in, this pump helps to keep a more negative (less positive) environment inside the cell.  • sodium-potassium pump is an electrogenic pump.  • electrogenic means "electric charge generating." 

  18. Na+K+ pump • purpose: cells able to send electrical signals to respond (react) to stimuli. • Is this passive or active transport? _________ (hint: is energy being used?) • Name 2 body systems that need to be able to respond to the environment. ______________

  19. Vesicles Move Large Substances Across Membranes (exocytosis) http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBooktransp.html#The%20Cell%20Membrane

  20. Phagocytosis: a type of endocytosis Phagocytosis of a Reproducing Bacterium by an Amoeba Neat website of amoeba eating by phagocytosis http://www.ivyhall.district96.k12.il.us/4th/kkhp/Microbes/amoeba1.html#AeatsP

  21. Membrane Receptor Proteins Receive Information • Functions of receptor proteins • Changes in permeability – may cause the ion channel to open to allow certain ions to cross the membrane • Second messengers – causes formation of second messenger inside the cell to activate chemical reaction • Enzyme action – may speed up chemical reactions inside the cell

  22. Vesicles move substances across membranes.

  23. Paramecium’s Contractile Vacuole • http://www.northland.cc.mn.us/biology/Biology1111/animations/transport1.html

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