diffusion & osmosis

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Diffusion & Osmosis. Schema Activator. Evaluate the following claims: 9 out of 10 people surveyed say that the bag lunches at GPA are among the best they’ve ever had 100% of people surveyed say that cell phones and music players should not be allowed in schools - PowerPoint PPT Presentation


  • Diffusion & Osmosis

  • Schema ActivatorEvaluate the following claims:

    9 out of 10 people surveyed say that the bag lunches at GPA are among the best theyve ever had

    100% of people surveyed say that cell phones and music players should not be allowed in schools

    What questions come to mind when you read these statements?

  • Movement of MaterialsWe have looked at cells and the structures that help make and transport materials throughout the cellHow do the materials enter and leave the cell?Cell membrane- selectively permeablewrite what you think this means in your science notebooks

  • Define selectively permeable membraneA membrane that allows only certain materials to cross it Materials pass through pores in the membrane

  • Structure of Cell MembraneLipid bilayerHydrophilic headsHydrophobic tailsCarrier proteins

    The cell membrane has a unique structure that controls how things enter and leave the cell, referred to as the fluid mosaic model

  • How Materials MoveMaterials move through the cell membrane through a process called Diffusion

    Write down what you think diffusion is in your science notebook.


  • Define DiffusionThe movement of molecules from a area in which they are highly concentrated to a area in which they are less concentrated.

  • Draw a diagram of an example of diffusion we saw in class.

  • See an animation of diffusion here:http://lewis.eeb.uconn.edu/lewishome/applets/Diffusion/diffusion.html

  • Define osmosis

  • Define osmosisThe diffusion of water across a selectively permeable membrane.

  • Define osmosis Water moves from a high concentration of water (less salt or sugar dissolved in it) to a low concentration of water (more salt or sugar dissolved in it). This means that water would cross a selectively permeable membrane from a dilute solution (less dissolved in it) to a concentrated solution (more dissolved in it).


  • http://www.usd.edu/~bgoodman/Osmos.htm Define osmosis

  • Define osmosisIn this picture a red blood cell is put in a glass of distilled water (all water with no salt or sugar in it). Because there is a higher concentration of water outside the cell, water enters the cell by OSMOSIS. In this case too much water enters and the cell swells to the point of bursting open. In the end pieces of cell membrane are left in the water. http://www.usd.edu/~bgoodman/Osmos.htm

  • See an animation of osmosis here:http://lewis.eeb.uconn.edu/lewishome/applets/Osmosis/osmosis.html

  • For more information on diffusion & osmosis, click here:http://edtech.clas.pdx.edu/osmosis_tutorial/default.html

  • Types of Passive TransportDiffusionOsmosisFacilitated DiffusionCarrier ProteinsIon channelsSome always openSome gated


  • Why are osmosis & diffusion important?All living things have certain requirements they must satisfy in order to remain alive maintain homeostasisThese include exchanging gases (usually CO2 and O2), taking in water, minerals, and food, and eliminating wastes. These tasks happen at the cellular level.Molecules move through the cell membrane by diffusion

  • Active TransportIf passive transport is the movement of materials from an area of greater to lesser concentration, what do you suppose active transport is? Write your answer in your science notebook

    Types of Active Transport:Cell Membrane PumpsEndocytosisExocytosis


  • Endocytosis & Exocytosis

  • Review Osmosis & Diffusion Here: http://wappingersschools.org/WJH/teachers/science/Jim_Site/asignments/cells/diffusionetc/diffusion_osmosis.html

  • HomeworkRead pp. 95-100Do questions 1-6 on pg. 100

    Read pp. 100-104Do questions 1-6 on pg. 104