1. CHAPTER 2 THE CHEMISTRY OF LIFE

2. I.The Nature of Matter A. Atoms – the basic unit of matter; made up of 3 subatomic particles

4. 1. Proton – found in the nucleus, positive charge 2. Neutron – also found in the nucleus, no charge

5. 3. Electron – are in constant motion in the space around the nucleus, negative charge

6. B. Elements & Isotopes 1. Element consists of one type of atom, 100+ known, 1 or 2 letter symbol

7. 2. Isotope- atoms of an element with a different # of neutrons, some are radio- active (unstable nuclei)

8. 3. Chemical Compounds – 2 or more elements combined in definite proportions

10. a.NaCl - chemical formula for table salt b. Sodium (Na) is a silver metal & chlorine is a green gas

11. c. Salt is a white solid with different properties from either of the elements it is comprised of

12. 4.Chemical Bonds – atoms in compounds are held together by bonds involving the valence electrons

13. a.Ionic bond – one atom (Na) transfers an electron to another (Cl)

14. b. Covalent bond – atoms share electrons

15. c.Van der Waals Forces – a slight attraction between oppositely charged portions of nearby molecules

16. Why does ice float?

17. II. Properties of Water A. The Water Molecule (H 2 O) 1. Polarity – water is polar because of the uneven distribution of electrons between the O and the H, the

18. O end is slightly – and the H end is slightly + 2. Hydrogen bonds- weaker, up to 4 bonds possible at once, this is responsible for adhesion and cohesion

19. B. Solutions & Suspensions 1. 2 types of mixtures can be made with water a. Solution Ex. salt in H 2 0

20. Na & Cl ions are attracted by the polar H 2 0 molecules & become dispersed (H 2 0 is the solvent & salt is the solute)

21. b. Suspensions – some materials don’t dissolve but separate into pieces small enough not to settle out

22. C. Acids, Bases, & pH 1. pH scale - gives concentration of H + ions; range 0-14

24. 2. Acids – a compound that forms H + ions in solution; pH below 7

25. 3. Bases – forms hydroxide (OH - ) ions in solution; pH above 7 4. Buffers – cells need pH 6.5- 7.5; buffers

26. prevent too much change in pH

27. III. Carbon Compounds A. Chemistry of C 1. C can bond with many elements including other C, has 4 valence electrons

29. B. Macromolecules 1. Formed by polymerization, a process of mono- mers joining to make polymers

30. Glucose Starch Carbohydrates

31. 2. Carbohydrates a. Made up of C, H, and O in a ratio of 1:2:1 b. Used by living things as their main source of energy

32. c. Composed of monomers of sugars which can combine into starch polymers d. Single sugars= monosaccharide's starch=polysaccharide

33. 3. Lipids a. Composed of C and H b. Known as fats, oils, and waxes c. At least 1 C-C double bond makes a fat unsaturated

35. 4. Nucleic Acids a. Contain H, C, O, N, and P b. Monomers called nucleotides c. Store and transmit genetic information

36. DNA

37. 5. Proteins a. Contain N, C, H, and O b. Have an amino group(NH 2 ) & a carboxyl group (COOH)

38. c. Amino acids (20+) are the monomers which make up the protein polymer d. Protein uses 1) Control the rate of reactions

39. 2) Regulate cell processes 3) Form bones & muscles 4) Transport substances 5) Fight disease