1. Biochemistry Chemical reactions in living things.

2. Water Water is the most important inorganic compound in living things because….. Most cellular activities take place in water solutions

3. Water Polar molecule - has polar covalent bonds. O has a slight (-) charge H has a slight (+) charge (-) O H H (+) (+) Polar water molecules interact with each other by forming hydrogen bonds.

4. Properties of Water Cohesion: the tendency of molecules to stick together.

5. Properties of water (con’t) Adhesion: the attractive force between different substances. Example: trees transport water from roots to leaves.

6. Properties of water (con’t) Surface tension: a measure of how difficult it is to break the surface of a liquid. insects “walk” on the surface of water.

7. Properties of water (con’t) High heat capacity: has ability to resist temperature change. the ocean stores heat from the sun and gives it off during cooling, keeping the climate more mild.

8. Properties of water (con’t) Good solvent: dissolves many solutes in all cells, blood, and plant sap.

9. the concentration of hydrogen ions in solution Water molecules dissociate into ions (H+) and (OH-) pH

10. pH (con’t) Acid- chemical compound that donates H+ atoms to solution Base- compound that accepts H+ atoms and removes them from solution

11. pH (con’t) pH scale 0-14 range 7 neutral 0-7 acidic 7-14 basic

12. pH (con’t) In organisms, the pH must be maintained: blood 7.4, stomach acid 2.0 pH can affect the rate and nature of internal chemical reactions.