Chapter 2 The Chemistry of Life

1. Chapter 2The Chemistry of Life CP Biology

2. Chapter 2:The Chemistry of Life • 2.1: The Nature of Matter • 2.2: Properties of Water • 2.3: Carbon Compounds • 2.4: Chemical Reactions and Enzymes

3. 2.1The Nature of Matter

4. What is an Atom??? the smallest unit of an element, having all the characteristics of that element

5. Structure of the Atom ________________ Center of the atom Contains protons & neutrons Positive charge ________________ Positive charge Located inside of the nucleus ________________ Neutral charge Located inside of nucleus ________________ Negative charge Located outside of the nucleus in energy levels

6. Size of Particles(smallest  largest) Quarks & Leptons Quarks Positive charge Have antiquarks (opposite of quarks – negative charge) Make up protons and neutrons, but not electrons Leptons Most well known lepton is the electron Subatomic particles Protons, neutrons, and electrons Atoms Made up of subatomic particles Elements Made up of atoms Compounds 2 or more elements

7. Elements and Compounds • _____________ • Cannot be broken down into simpler substances • Organized on the Periodic Table • Fe, H, O, Hg, Cu • _____________ • 2 or more elements combined • Properties differ from the properties of their component elements • H2O, CO, FeCl3

8. Atomic Number Identifies an element Tells the number of protons Tells the number of electrons in a neutral atom How the P.T. is arranged Example: Neon 10 p, 10 e-, 10 n

9. Atomic Mass Number Mass of an element Tells the number of protons and neutrons in an element May change Isotopes: atoms of the same element with different masses (different # neutrons) Decimal Number Example: Argon 39.9amu 18, p, 18 e-, 22 n

10. Practice ProblemsAtomic # & Atomic Mass #

11. Isotopes Have the same atomic number, different mass Same # protons Different # neutrons

12. Practice ProblemsIsotopes

13. Ions • ___________: charged atoms • ____________: • positive ion • Gives away electrons • Example: Ca+2 • ___________: • Negative ion • Gains electrons • Example: N-3

14. Types of Chemical Bonds • Ionic Bonds • Covalent Bonds • Van der Waals Forces • Metallic Bonds • Between 2 metals • __________: mixture of 2 or more metals

15. Ionic transfers e- between a metal and nonmetal (+ and -) force binds opposite charged ions together conduct electricity when in solution at room temp, most are crystalline in structure high melting and boiling point hard, rigid, brittle solids Covalent shares e- usually between 2 nonmetals (- and -) do not conduct electricity in solution Polar or Nonpolar Polar: when e- are NOT shared equally IONIC vs. COVALENT BONDS

16. Van der Waals Forces • When molecules are close together, a slight attraction develops between the oppositely charged atoms • Weaker than ionic and covalent bonds

17. 2.2Properties of Water

18. H2O # Lone Pairs = 2 # Bonding Pairs = 2 Bond angle = 104.5° Shape = Bent Modification of tetrahedral Example: Water

19. How does the structure of water contribute to its unique properties? • _________________: does not share its electrons equally • ___________________: attraction between a hydrogen atom on one water molecule to a hydrogen atom on another water molecule

20. Water’s Special Properties • ________________: • Is an attraction between water molecules of the same substance • _______________: • Is an attraction between molecules of different substances • ________________: • Takes a large amount of heat energy to cause water molecules to move quickly to heat up

21. Solutions and Suspensions

22. Mixtures • Can be solids, liquids, or gases • Types of mixtures • Homogeneous mixture • Heterogeneous mixture • Colloid • Suspension

23. Homogeneous Mixtures(SOLUTIONS) • uniform throughout • a.k.a. _____________ • ___________: part being dissolved • ___________: part doing the dissolving ***WATER IS THE UNIVERSAL SOLVENT • Other examples: • iced tea • lemonade

24. Heterogeneous Mixtures • not uniform throughout • individual substances remain unique • Examples: • chef salad • Sand and water

25. Colloids & Suspensions • ___________: Mixtures that contain tiny, fine particles that reflect light • _________________: when particles in a mixture reflect light • Example: milk • ______________: when mixtures separate • Example: Italian salad dressing

26. Tyndall Effect

27. Acids, Bases, and pH

28. Acids • pH range 0-7 • Produces H+ ions • Taste sour • Turn litmus paper pink/red • Corrosive • React with bases to form salts • examples: • Most foods (tomatoes, lemons, etc) • Battery acid • Stomach acid

29. Bases • produces [OH- ]] ions • tastes bitter • slippery • pH: beyond 7.0 -14 but not including 7.0 • turns litmus paper blue • combines with acids to form salts • electrolytes • can be corrosive • examples: cleaning supplies, eggs, seawater

30. pH Scale The pH scale is a measure of the [H+] ion concentration in a substance pH colors – ROYGBIV (red – very acidic green-neutral violet –very basic)

31. pH scale continued. . . • pH 1-3/4 • very strong acids • pH 5-6 • weak acids • pH 7 • neutral solutions • pH 7-10/11 • Weak alkaline solutions • pH 11-14 • Strong alkaline solutions

32. pH values of common substances

33. ExampleWhat is the pH value of A-D?

34. Buffers • Buffers • Weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in __________ • Example: • Blood has a pH of 7.4 • Changes in blood pH are usually prevented by blood buffers such as bicarbonate and phosphate ions

35. 2.3Carbon Compounds

36. Organic Chemistry • Organic Chemistry: • The study of compounds that contain bonds __________________ atoms

37. Carbon • Has _____ valence electrons • Electrons in the outer most energy level involved in bonding • One carbon atom can bond to another to make chains and branches

38. 4 Groups _________________ _________________ _________________ _________________ Macromolecules are made from thousands of smaller molecules ______________ join together to form ______________ Macromolecules

39. Carbohydrates • Made up of carbon, hydrogen and oxygen atoms usually in the ratio 1:2:1 • Living things use carbs as their main source of energy • Structure: rings or chains • Types: • __________________ (glucose) 5-6 carbons • _____________ (sucrose) 10 or more carbons

40. Examples of Carbohydrates

41. Lipids • Not soluble in water • Used to store energy • Make up some biological membranes • Examples: fats, steroids • Types: • ____________: all single bonds • ____________: double and/or triple bonds

42. Nucleic Acids • Contain carbon, oxygen, nitrogen, hydrogen, and phosphorus • Are polymers made from nucleotides • __________________: • A five carbon sugar • Phosphate group (PO4-3) • and a nitrogen base • Store and transmit heredity • Examples: ________________

43. Proteins • Contain carbon, nitrogen, hydrogen, and oxygen • Made up of long chains of amino acids • _______________: • Compounds with an amino group (-NH2) • More than 20 in nature • Some control the rates of reactions and regulate cell processes • Some form cell structures

44. Protein Structure

45. 2.4Chemical Reactions and Enzymes

46. What is a chemical reaction? • ____________________________________________________________________

47. Evidence of a Chemical Reaction • Color change • Effervescence • Evolution of gas

48. Evidence of a Chemical Reaction continued. . . • Evolution of light • Odor • New substance forms • Formation of a Precipitate

49. Evidence of a Chemical Reaction continued. . . • Temperature change Exothermic/Spontaneous Reaction • Heat is given off • Heat/energy are products • Example: hot pack • Endothermic/Nonspontaneous Reaction • Heat is absorbed • Heat/energy are reactants • Example: cold pack

50. Parts of a Chemical Reaction ~ 2H2 + O2 2H2O Reactants: elements or compounds to the left of the arrow that combine together in a chemical reaction Products: elements or compounds to the right of the arrow that are produced in a chemical reaction Coefficient: large number before a chemical symbol Subscript: small lowered number after a chemical symbol : yields or produces Catalyst: symbol written above the arrow; speeds up rxn ∆: heat ~: electricity Pt: platinum