1. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint TextEdit Art Slides for Biology, Seventh Edition Neil Campbell and Jane Reece Water and its Properties What properties of water account for proper hydration of the branches in a 150 foot tree? Why do you add salt to the water you are boiling for spaghetti?

2. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.2 Hydrogen bonds between water molecules Hydrogen bonds  + + ++ H H ++ ++ –– –– –– ––

3. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.3 Water transport in plants Water conducting cells 100 µ m

4. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.4 Walking on water

5. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.5 Ice: crystalline structure and floating barrier Liquid water Hydrogen bonds constantly break and re-form Ice Hydrogen bonds are stable Hydrogen bond

6. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.6 A crystal of table salt dissolving in water Negative Oxygen regions of polar water molecules are attracted to sodium cations (Na + ). + + + + Cl – – – – – Na + Positive hydrogen regions of water molecules cling to chloride anions (Cl – ). + + + + – – – – – – Na + Cl –

7. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.7 A water-soluble protein This oxygen is attracted to a slight positive charge on the lysozyme molecule. This oxygen is attracted to a slight negative charge on the lysozyme molecule. (a) Lysozyme molecule in a nonaqueous environment ( b) Lysozyme molecule (purple) in an aqueous environment such as tears or saliva (c) Ionic and polar regions on the protein’s Surface attract water molecules. ++ ––

8. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Reaction producing hydroxide and hydronium ions H Hydronium ion (H 3 O + ) H Hydroxide ion (OH – ) H H H H H H + – +

9. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Group Problem I I would like to make a 1L solution (in water) of 0.1M NaOH. The formula weight of NaOH is 40g/M If I wanted a 0.25L solution of 0.1M NaOH, how might I make this?

10. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.8 The pH scale and pH values of some aqueous solutions Increasingly Acidic [H + ] > [OH – ] Increasingly Basic [H + ] < [OH – ] Neutral [H + ] = [OH – ] Oven cleaner 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH Scale Battery acid Digestive (stomach) juice, lemon juice Vinegar, beer, wine, cola Tomato juice Black coffee Rainwater Urine Pure water Human blood Seawater Milk of magnesia Household ammonia Household bleach

11. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.9 Acid precipitation and its effects on a forest 0101 2323 4545 6767 8989 10 11 12 13 14 More acidic Acid rain Normal rain More basic

12. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint TextEdit Art Slides for Biology, Seventh Edition Neil Campbell and Jane Reece Group Problem II The normal pH of the blood is 7.4. What might be the effect of a sudden change in pH to 6.4? What kind of change in H+ concentration does this represent? Does the body have any mechanisms to compensate for changes in H+ concentration?