Chemistry of Life Unit

1. Chemistry of Life Unit When water, H2O, is created, hydrogen and oxygen share the electrons • The oxygen has a slightly negative charge • The hydrogen’s have a slightly positive charge This uneven pattern of charge creates a polar molecule = has a positive side and negative side

2. Water Molecule _ O H H + +

3. Hydrogen Bonding Hydrogen Bond = an attraction between a slightly positive hydrogen atom and a slightly negative atom, often oxygen or nitrogen

4. Hydrogen Bonding Hydrogen Bond

5. Properties Related to Hydrogen Bonding Life depends on hydrogen bonds in water • High Specific Heat = water resists changes in temp. - helps regulate cells

6. Properties Related to Hydrogen Bonding (cont) • Cohesion = attractive forces between particles of the same kind - example: surface tension of water • Adhesion = the attractive forces between unlike substances - example: meniscus curve in a graduated cylinder

7. Surface Tension

8. Meniscus Curve

9. Properties Related to Hydrogen Bonding (cont) • Capillarity = the ability of water to move up through narrow tubes against gravity - due to cohesion and adhesion - example: carnations turning a different color in colored water

10. Carnations in Colored Water

11. Carnations in Colored Water

12. Solutions The polarity of water makes it very effective at dissolving many substances Solvent + Solute = Solution Concentration [ ] = amount of solute in a given amount of solvent Saturated = no more solute will dissolve in the solvent

13. Solvent + Solute = Solution Solution

14. Mosquito injects a solution into your body that prevents clotting

15. Solutions (cont) Water is the universal solvent. All processes necessary for life take place in water.

16. Acids and Bases Acid = compound that releases a hydrogen ion (H+) when dissolved in water - increases the H+ [ ] Base = compound that remove H+ ions from a solution - lowers the H+ [ ]

17. Acids and Bases (cont) pH scale = amount of H+ ions in a solution 0 to 6 = acidic 7 = neutral 8 to 14 = basic buffer = compound that regulates H+ [ ] - maintains homeostasis

18. pH Scale

22. Organic Compounds Carbon is the building block of life - can form multiple bonds (up to 4), including other carbon atoms More than 90 % of the mass of all living things are composed of combinations of just 4 elements 1) Carbon ( C) 2) Hydrogen (H) 3) Oxygen (O) 4) Nitrogen (N)

24. Examples sugars starches cellulose glycogen Specifics - contain C, H, and O - main source of usable chemical energy for cells - major part of plant cell wall (made of cellulose) - most basic are simple sugars = monosaccharides (glucose) - bond to form polysaccharides 1) Carbohydrates

25. 1) Carbohydrates Glucose

26. Examples Fats Oils Cholesterol Specifics - contain C, H, and O - store large amounts of energy - cell membrane made up of phospholipids - regulate body responses and control sexual development - are nonpolar molecules (don’t dissolve in water) 2) Lipids

28. Saturated Fats (solid at room temp)

29. Unsaturated Fats (liquid at room temp)

30. Examples Specifics - contain C, H, O, and N - made of monomers called amino acids - 20 different amino acids build proteins - specific sequence determines structure and function 3) Proteins

31. Red Blood Cells and Sickle Cell Anemia(SEM 3500x)

32. Functions: – stores info to build proteins – helps build proteins Types: 1) DNA 2) RNA 4) Nucleic Acids- work together to make proteins

33. Chemical Reactions = change substances into different substances by breaking and forming chemical bonds

34. 6O2 + C6H12O6 6CO2 + 6H2O 1. Reactants = substances changed during a chemical reaction (left side) 2. Direction 3. Products = substances made during a chemical reaction (right side)

35. Bond Energy = the amount of energy that will break a bond Chemical Equilibrium = when both the reactants and products are made at the same rate * Chemical reactions release or absorb energy

36. Types of Chemical Reactions Activation Energy = the amount of energy needed to start a reaction - is very high in most chemical reactions (especially in the body)

37. Activation Energy

38. Types of Chemical Reactions (cont) Exothermic = chemical reaction that releases more energy than it absorbs - gives off heat (hot) - ex: cellular respiration

39. Exothermic Reaction 5 6 7 4

40. Types of Chemical Reactions (cont) Endothermic = chemical reaction that absorbs more energy than it releases - absorbs heat (cold) - ex: photosynthesis

41. Endothermic Reaction 9 10 8 11

42. Enzymes Catalyst = substance that reduces the amount of activation energy that is needed to start a chemical reaction Catalysts are not changed during a chemical reaction Enzymes = a type of catalyst in living things

43. Enzymes - almost all are proteins - work best in normal body conditions (temp. and pH) - specific shape allows only certain reactants to bind - fit like a lock and key

44. Lock and Key Model - Enzymes

45. Enzymes (cont) - functions: 1) help bring substrates together and chemical reactions occur 2) decrease the activation energy of the reaction 3) increase the rate of the reaction

46. Enzymes reduce Activation Energy

47. Enzymes (cont) - Reaction 1 requires more activation energy than Reaction 2 - Reaction 3 has less activation energy due to a catalyst being used