1. POLAR MOLECULES! Water A molecule with an unequal distribution of charge; each molecule has a +’ve charge and a –’ve charge H bond- weak bond found in LOTS of biomolecules

2. Importance of Water Water resists temp change Requires more heat to increase in temp Looses a lot of heat when it cools Water expands when it freezes Important to what animals???

3. Brownian Motion: Pollen grains moved…. A life force?? No other things move too! So what IS it? Random motion of atoms and molecules Characteristics of liquids, solids, and gases

4. Diffusion mvmt of molecules from high conc. to low conc. Does NOT require energy Ex: food coloring in water, smells of cake baking from an oven, cold air from the freezer to your hot house in the summer, etc. Also responsible for mvmt of materials across cell membrane

5. Diffusion Three key factors affect diffusion rate: 1. concentration 2. temp 3. pressure Conc. Increase will… Increase or decrease diffusion rate?? Temp Increase will… Increase or decrease diffusion rate?? Pressure Increase will… Increase or decrease diffusion rate??

7. Dynamic Equilibrium- continuous mvmt but no overall concentration change

8. Do 1, 2-6 on p 156 in groups of 2