Lecture notes are given after the teacher demonstrations are presented to give specific information on the "mechanics" of diffusion and osmosis.

Cells have particular structures that underlie their functions. Every cell is surrounded by a membrane that separates it from the outside world. Inside the cell is a concentrated mixture of thousands of different molecules which form a variety of specialized structures that carry out such cell functions as energy production, transport of molecules, waste disposal, synthesis of new molecules, and the storage of genetic material.

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The use of an overhead projector and verbal discussion would best facilitate giving notes since it incorporates two learning styles.

*Check notebooks for completion of notes *Create concept maps *Quiz over material

Diffusion and Osmosis Notes *Cells maintain a biological balance, HOMEOSTASIS, by controlling and regulating what gets into and out of the cell. *MOLECULAR THEORY OF MATTER - all matter is made up of molecules which are in constant motion. -travel in straight lines until they hit somehting and then rebound -move from areas of high concentration to low concentration *DIFFUSION - movment of molecules from an area of greater concentration ton one of less concentration - gradully all molecules are evenly mixed. *CONCENTRATION GRADIENT is the difference in concentrations of a substance across space *EQUILIBRIUM is reached when the concentration of molecules of a substance is the same throughout a space *Cell membranes allow some substances to pass in or out; this is referred to as SELECTIVELY PERMEABLE or SEMIPERMEABLE. - depends on: size of molecule type of moleule structire of membrane *OSMOSIS - process by which WATER molecules diffuse through a MEMBRANE from an area of greater concentration to an area of lesser concentration *SOLUTE - substance dissolved in a solution *SOLVENT - liquid part of aq solution (often water) *The direction of movment during osmosis depends on the concentration of water and solutes in a solution. *HYPOTONIC - "lower"; if the concentrations of solute outside the cell is lower than in the cell water will move into the cell *HYPERTONIC - "higher"; if the concentrations of solute outside the cell is greater than inside the cell; water will move out of the cell *ISOTONIC - "equal"; when the concentrations of solute inside and outside the cell is equal; there is not net movement of water *TURGOR PRESSURE occurs when water diffuses into a plant cell causing it to become rigid and increasing the pressure within the cell. This forces the cytoplasm and cell membrane against the cell wall. *If a cell takes on too much water it will burst; this process is called CYTOLYSIS. *If water leaves a cell, it will shrink; this process is called PLASMOLYSIS. *CONTRACTILE VACUOLES - organells that help rid a cell of excess water

Technology Requirements/Integration  (help)

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