Membranes SWBAT describe the structure and composition of a cellular membrane; differentiate between passive and active transport of substances through the membranes of a cell; describe the process of diffusion and osmosis

Review Read page 49 In your lab notebooks make a list of what you already know about cells.

Membranes Cell membrane A thin covering that forms the outer boundary of the cell

Cell membranes proteins lipid bilayer

Get out your lab notebooks Title Properties of cell membranes As we talk about each property we will do a lab demonstration, record the appropriate information in your lab notebooks.

Cell Membrane Properties Selective permeability Certain molecules go through them and other molecules to not In your lab notebook draw an illustration of the following demonstration and then answer the following questions under the subtitle Selective Permeability 1. What do the m & m’s represent? 2. What does the sugar represent? 3. What does the strainer represent? 4. How did this illustrate selective permeability?

Cell Membrane Properties Diffusion The movement of molecules from a place of high concentration (lots of molecules) to places of low concentration (few molecules) Turn to page SA Send one person in your group to get the two beakers of water Send another person to get the food color and a stirring rod. Have one person use their phone or ipod to time the experiment

Cell Membrane Properties Osmosis The diffusion of water through a selectively permeable membrane Turn to pages SA Record the information in your lab notebooks as the demonstration continues.

Cell Membrane Properties Active Transport Requires the cell to use its own energy to move substances through the membrane Passive Transport The movement of substances through a membrane without the use of a cell’s own energy.