1. Chemistry Everything in life is either chemistry or physics Dr. M. Diamond

2. Atoms Nucleus –protrons (+) charge neutrons no charge Electrons –negative charge –orbit in shells

3. Isotopes Different numbers of neutrons –Mass # = protons + neutrons –Atomic # = protons

4. Radioisotopes Decay at a predictable rate Beta particle released turning a neutron into a proton Half-life – the amount of time it takes for half of the radioisotopes to decay –Half-life for C 14 = 5730 yrs. – good for dating things that are up to about 60k yrs Should never reach 0

5. What are you? Mostly H, O, C, N H 9.5% C 18.5% O 65% N 3.2%

6. Molecules Two or more atoms bonded together May be compound (different types of atoms) Compounds have properties different from their components

7. Bonding Ionic – electron donation

8. Bonding (your mother told you to SHARE!) Covalent - methanewater

9. Bonding (weak and weaker) Hydrogen (weak)Van der Waal’s (weaker)

10. More on covalent bonds Electrons –Shared equally results in a non-polar molecule (e.g., carbon dioxide) –Shared unequally results in a polar molecule (e.g., water)

11. Water Polar molecule Water molecules are attracted to each other And to other polar molecules

12. Water solvency Water attracts other polar molecules Repels non-polar An excellent solvent –Because of polarity –Most chemical substances will dissolve in water –More will dissolve in water than any other liquid

13. Interactions

14. More Interactions

15. How does this affect cell membranes? Orientation of mem- brane components Orientation of proteins in membrane

16. Other properties Cohesion – attraction to other water molecs. Adhesion – attraction to other surfaces

17. Heat Capacity The quantity of heat required to produce a unit change of temperature (1 o C) in a unit mass (1 g) of material Very high in water because of H bonding

18. What is pH? Concentration of H+ ions (or OH-) pH = the negative log of the H+ ion concentration in moles/L The higher the H+ concentration, the lower the pH (acidic) The lower the H+ concentration (and higher OH- conc.) the higher the pH (basic or alkaline) pH 7 is neutral

19. More on pH Here’s the math explanation

20. Buffers Help maintain pH –Accept xs H + or –Donate H + –Very important for cell functioning