1. Cell Membranes Osmosis and Diffusion

2. Functions of Membranes 1. Protect cell 2. Control incoming and outgoing substances 3. Maintain ion concentrations of various substances 4. Selectively permeable - allows some molecules in, others are kept out

3. Phospholipid Bilayer

4. Fluid Mosaic Model

5. Solutions Solutions are made of solute and a solvent Solvent - the liquid into which the solute is poured and dissolved. We will use water as our solvent today. Solute - substance that is dissolved or put into the solvent. Salt and sucrose are solutes.

6. Methods of Transport Across Membranes 1. Diffusion -passive transport - no energy expended 2. Osmosis - Passive transport of water across membrane 3. Facilitated Diffusion - Use of proteins to carry polar molecules or ions across 4. Active Transport- requires energy to transport molecules against a concentration gradient – energy is in the form of ATP

7. Diffusion Movement of molecules from an area of high concentration to an area of low concentration. Movement from one side of a membrane to another, un-facilitated

8. Diffusion

9. Osmosis

10. Tonicity is a relative term Hypotonic SolutionHypotonic Solution - One solution has a lower concentration of solute than another. Hypertonic SolutionHypertonic Solution - one solution has a higher concentration of solute than another. Isotonic SolutionIsotonic Solution - both solutions have same concentrations of solute.

11. Plant and Animal Cells put into various solutions

12. Types of Transport

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