The document discusses the key biomolecules that are essential for life. It begins by introducing atoms and how they bond to form molecules. It then focuses on four classes of important organic compounds - carbohydrates, lipids, proteins, and nucleic acids. Carbohydrates include sugars and starches, lipids include fats and oils, proteins determine structure and function, and nucleic acids contain our genetic code and direct protein production. Water is also described as central to life due to its role in chemical reactions and as a solvent.

1. Atoms, Molecules, and Life

2. electron shell Carbon (C) Oxygen (O) Phosphorus (P) Calcium (Ca)

3. Phosphorus (P) Calcium (Ca)

4. (b) Sodium ion (+) Chlorine ion (–) Attraction between opposite charges

5. (c) An ionic compound: NaCl

8. electron nucleus Hydrogen (H) Helium (He)

11. (a) Sodium atom (neutral) Chlorine atom (neutral) Electron transferred

12. (a) (b) (c) Sodium atom (neutral) Chlorine atom (neutral) Sodium ion (+) Chlorine ion (–) Electron transferred Attraction between opposite charges An ionic compound: NaCl

14. (a) nonpolar covalent bonding (b) polar covalent bonding (slightly negative) (slightly positive) Water (H–O–H or H 2 O), a polar molecule Hydrogen (H–H or H 2 ), a nonpolar molecule Oxygen (O=O or O 2 ), a nonpolar molecule

15. (a) nonpolar covalent bonding Hydrogen (H–H or H 2 ), a nonpolar molecule Oxygen (O=O or O 2 ), a nonpolar molecule

16. (b) polar covalent bonding (slightly negative) (slightly positive) Water (H–O–H or H 2 O), a polar molecule

18. hydrogen bonds

24. hydroxide ion (OH – ) hydrogen ion (H + ) water (H 2 O)

25. stomach acid, lime juice lemon juice “ acid rain” (2.5-5.5), vinegar, cola, orange juice, tomatoes beer black coffee, tea normal rain (5.6), pure water (7.0), saliva, blood, sweat (7.4) seawater (7.8-8.3) baking soda phosphate detergents chlorine bleach, milk of magnesia household ammonia, some detergents (without phosphates) washing soda oven cleaner 1-molar sodium hydroxide (NaOH) 1-molar hydrochloric acid (HCl) urine (5.7)

27. electron shell Carbon (C) Oxygen (O)

29. Dehydration synthesis

31. Hydrolysis

34. glucose fructose sucrose Dehydration synthesis

35. individual cellulose molecules bundle of cellulose molecules hydrogen bonds cross-linking cellulose molecules cellulose fiber

38. fatty acids glycerol 3 water molecules

39. Beef fat (saturated) carbon hydrogen oxygen

40. Peanut oil (unsaturated)

41. Cardiovascular diseases Evidence is accumulating that increasing omega-3 fatty acid intake can decrease the risk of cardiovascular diseases by 1) preventing arrhythmias that can lead to sudden cardiac death, 2) decreasing the risk of thrombosis (blood clot formation) that can lead to heart attack or stroke, 3) decreasing serum triglyceride levels, 4) slowing the growth of atherosclerotic plaque, 5) improving vascular endothelial function, 6) lowering blood pressure slightly, 7) decreasing inflammation. The American Heart Association found the evidence discussed below convincing enough to recommend that all adults eat a variety of fish, particularly oily fish, at least twice weekly, in addition to consuming vegetable oils rich in ALA

44. fatty acid tails (hydrophobic) polar head (hydrophilic) glycerol backbone

45. estradiol cholesterol testosterone

48. amino group carboxyl group variable group hydrogen

49. amino group amino acid amino acid amino group carboxyl group carboxyl group peptide bond peptide water

50. Peptide chain of amino acids folds into complex shape two or more folded chains may join to form a complex protein

52. Peptide chain of amino acids folds into complex shape

53. Two or more folded chains may join to form a complex protein.

57. phosphate base Deoxyribose nucleotide sugar

58. phosphate base Nucleotide chain sugar