1. C HEMICAL C ONTEXT OF L IFE AP Biology Ch 2

2. C H. 2 BEGINS The amazon rain forest in South America is a showcase for the diversity of life on earth. Colorful birds, insects, and other animals live in a densely-packed environment of trees, shrubs, vines, and wildflowers and an excursion along a waterway or a forest path typically reveals a lush variety of plant life…

3. B IOLOGY HEARTS C HEMISTRY Luciferin (Firefly) Pyrethrin (Chrysthanthemum) Batrachotoxin (Golden Dart Frog)

4. M ATTER & M ASS Matter is anything that has mass & takes up space

5. A TOMS Smallest unit of matter Proton: positive Neutron: neutral Electron: negative

6. B IOLOGICAL I MPORTANCE OF A TOMS Electrons: hold potential energy valence e-

7. E LEMENTS A collection of atoms substances 25 elements essential to life

8. CHNOPS C: building block H: provide energy N: amino acids O: cellular respiration P: DNA & energy S: protein structure

9. C OMPOUND Two or more elements combined in a fixed ratio

10. C HEMICAL BONDS Covalent: sharing electrons Polar (H2O) Nonpolar (Lipids, Oils) Ionic: transferring electrons NaCl Hydrogen: weak involve H Van der Waals: weakest give proteins 3D shape

11. B IOLOGICAL ELEMENTS

12. A RE YOU A SOLID, LIQUID, OR GAS ?

13. W ATER Chapter 3

14. W ATER IS ESSENTIAL TO LIFE

15. B IOLOGICAL I MPORTANCE OF W ATER Life evolved in water All cells still contain water Biochemical reactions occur in water

16. P OLAR C OVALENT B OND H 2 O doesn’t share e- evenly Oxygen atom is electronegative Hydrogen atoms are slightly positive + + -

17. H YDROGEN B ONDING Occurs when two water molecules interact This bonding type allows water to have unique properties vital for living things

18. P ROPERTIES OF W ATER

19. 1. C OHESION & A DHESION Water molecules stick together & other molecules Important for: Surface tension Capillary action

20. 2. G OOD SOLVENT Water dissolves other polar molecules Salt, glucose, and enzymes Water does not dissolve nonpolar molecules Lipids

21. 3. M ODERATION OF T EMPERATURE Water has a high specific heat a lot of energy is required to change its temperature. Water creates stable environment

22. 4. H EAT OF VAPORIZATION & FUSION Water evaporates if provided with energy Sweating removes heat from living organism Water freezes if provided with energy Cells resist freezing

23. 5. F LOATING ICE INSULATES WATER Less dense as solid than liquid

24. 6. W ATER D ISASSOCIATES H shifts from one H 2 O molecule to another Result: a hydronium ion (+) & a hydroxide ion (-) Buffers protect life from extreme pH solutions