1. The Chemistry of Life

3. Objectives What three subatomic particles make up atoms? How are all the isotopes of an element similar? What are the two types of chemical bonds?

4. The Big Idea Life Depends on chemistry Chemical reactions keep you alive

5. Atom Basic unit of matter

6. Democritus Atomic Theory The theory states that these atoms are all individually created and cannot be separated, no matter what scientific procedures are applied.

7. Subatomic particles Protons - Neutrons - Electrons - Positively charged (+) Not charged (neutral) Negatively charged (-) Bind together to form the nucleus Electrons Protons Neutrons Nucleus

9. Element A pure substance that consists of just one type of atom

11. 6 C Carbon 12.011 Atomic number An elements Atomic Number = number of protons

12. Isotope Atoms of the same element that differ in the number of neutrons they contain

13. Nonradioactive carbon-12Nonradioactive carbon-13Radioactive carbon-14 6 electrons 6 protons 6 neutrons 6 electrons 6 protons 8 neutrons 6 electrons 6 protons 7 neutrons

14. 6 C Carbon 12.011 Mass number The Sum of protons and neutrons in the nucleus of an atom is its MASS NUMBER

15. The weighted average of the masses of an elements isotope is called its atomic mass

16. Radioactive isotopes Can be dangerous Can be used practically Radioactive dating Treat cancer Kill bacteria

17. Compounds A substance formed by the chemical combination of two or more elements in definite proportions Ex) H 2 O, NaCl

18. Sodium – silver colored metal, soft enough to cut with a knife

19. Sodium reacting explosively in water

20. Chlorine – poisonous green gas used to kill many people in WWII

21. Combination of sodium and chlorine

22. Table Salt

24. Ionic Bonds Formed when one or more electrons are transferred from one atom to another

25. Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na + ) Chloride ion (Cl - ) Transfer of electron Protons +11 Electrons -11 Charge 0 Protons +17 Electrons -17 Charge 0 Protons +11 Electrons -10 Charge +1 Protons +17 Electrons -18 Charge -1

26. If an atom loses an electron it becomes positive If an atom gains an electron it becomes negative

27. Ions Positively and negatively charged atoms

28. Covalent Bonds Forms when electrons are shared between atoms

29. Molecule The structure that results when atoms are joined together by a covalent bond Smallest unit of most compounds

30. Van der Waals Forces A slight attraction that develops between the oppositely charged regions of nearby molecules due to unequal sharing of electrons

32. 1. Describe the structure of an atom. Atoms are made up of protons and neutrons in a nucleus. Electrons are in constant motion in the space around the nucleus. 2. Why do all isotopes of an element have the same chemical properties They have the same number of electrons

33. 3. What is a covalent bond? A bond formed when electrons are shared between atoms 4. What is a compound? How are they related to molecules A compound is a substance formed by the chemical combination of two or more elements in definite proportions. A molecule is the smallest unit of most compounds

34. 5. How do Van der Waals forces hold molecules together? When the sharing of electrons are unequal, a molecule has regions that are charged. An attraction can occur between oppositely charged regions of nearby molecules

35. 6. How are ionic bonds and Van der Waals forces similar? How are they different? In both cases, particles are held together by attractions between opposite charges. The difference is that ionic charges are stronger

37. Objectives Why are water molecules polar? What are acidic solutions? What are basic solutions?

38. The Big Idea Much of our planet is covered in water Water is necessary for life to exist If life exists on other planets, there most likely is water present Water has many properties that make life possible

39. Polarity (-) (+) The oxygen atom has a stronger attraction for electrons

40. Hydrogen Bonds Because of waters partial charges, they can attract each other and create hydrogen bonds Not as strong as covalent or ionic bonds Waters ability to create multiple hydrogen bonds gives it many special properties

41. Cohesion Attraction between molecules of the same substance

44. Adhesion Attraction molecules of different substances

46. Mixture Material composed of two or more elements or compounds that are physically mixed but not chemically combined Ex.) salt & pepper, earths atmosphere

47. Solutions Mixture of two or more substances in which the molecules are evenly distributed Ex.) salt water Settles out over time

48. Solutions Cl - Water Cl - Na + Water Na +

49. Solute Substance that is dissolved Ex.) salt

50. Solvent The substance that does the dissolving Ex.) Water

51. Suspensions Mixture of water and non-dissolved materials Ex.) sugar solution, blood Separate into pieces so small, they never settle out

52. The pH scale Indicated the concentration of hydrogen ions in a solution

53. Neutral Acid Base

54. Acids Any compound that forms H + (hydrogen) ions in solution

55. Base A compound that produces OH - (hydroxide) ions in solution

56. Buffers Weak acids or bases that can react with strong acids or bases to prevent sharp, sudden pH changes

58. 1. Use the structure of a water molecule to explain why its polar Oxygen atom has greater attraction for electrons, therefore the oxygen atom is negative and the hydrogen end is positive

59. 2. Compare acidic and basic solutions in terms of their H + ion and OH - ion concentrations Acid have more H + ions than OH - ions, and bases have more OH - ions than H + ions

60. 3. What is the difference between a solution and a suspension? In a solution, all components are evenly distributed. In a suspension, un-dissolved particles are suspended

61. 4. What does pH measure? The concentration of H + ions in a solution 5. The strong acid hydrogen floride (HF) can be dissolved in pure water. Will the pH of the solution be greater or less than 7? less than 7

63. Objective What are the functions of each group of organic compounds?

64. Life’s backbone Most of the compounds that make up living things contain carbon. In fact, carbon makes up the basic structure, or “backbone,” of these compounds. Each atom of carbon has four electrons in its outer energy level, which makes it possible for each carbon atom to form four bonds with other atoms. As a result, carbon atoms can form long chains. A huge number of different carbon compounds exist. Each compound has a different structure. For example, carbon chains can be straight or branching. Also, other kinds of atoms can be attached to the carbon chain. Section 2-3

65. MethaneAcetyleneButadieneBenzene Isooctane

66. Macromolecules “giant molecules” Formed by a process called polymerization

67. Monomers Smaller units

68. Polymers Linked up monomers

69. Carbohydrates Compounds made up of carbon, hydrogen, and oxygen atoms usually in a ratio of 1:2:1 Main source of energy The monomers of starch are sugars

70. Single sugar molecules are called monosaccharides The large macromolecules formed from monosaccharides are known as polysaccharides

71. Starch Glucose

72. Lipids Made mostly from carbon and hydrogen atoms Used to store energy

73. Lipid Glycerol Fatty Acids

74. Proteins Macromolecules that contain nitrogen as well as carbon, hydrogen, and oxygen Proteins are polymers of molecules called amino acids

75. Amino Acids General structureAlanineSerine Carboxyl group

76. More than 20 different amino acids, can join to any other amino acid The instructions for arranging amino acids into many different proteins are stored in DNA Each protein has a specific role The shape of proteins can be very important

77. Proteins Amino Acids

78. Nucleic Acids Macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorus Double Helix

79. Nucleotides Consists of 3 parts: 5-carbon sugar, phosphate group and nitrogen base Nitrogen Base 5-Carbon Sugar Phosphate group

80. 2 kinds of nucleic acids RNA (ribonucleic acids) – contains sugar ribose DNA (deoxyribonucleic acid) – contains sugar deoxyribose

82. 1. Name four groups of organic compounds found in living things carbohydrate, lipid, protein, nucleic acids 2. Describe at least one function of each group of organic compounds carbohydrates – energy lipids – store energy proteins – form tissue nucleic acids – transmit hereditary information

83. 3. Compare the structures and functions of lipids and starches Lipids are made from carbon and hydrogen. Starches are made of carbon, hydrogen and oxygen. They both can be used to store energy

85. Objectives What happens to chemical bonds during chemical reactions? How do energy changes affect whether a chemical reaction will occur? Why are enzymes important to living things?

86. The Big Idea Living things are made up of chemical compounds Everything that happens to an organism is based on chemical reactions

87. Chemical Reactions A process that changes or transforms one set of chemicals into another.

88. Reactants Elements or compounds that enter into a reaction.

89. Products Elements or compounds produced by a chemical reaction.

90. Example Reaction: Getting rid of Carbon Dioxide In the blood In the lungs CO 2 + H 2 0  H 2 CO 3 (carbonic acid) H 2 CO 3  CO 2 + H 2 O Released as you breathe

91. Energy in reactions Energy-Absorbing Reaction Energy-Releasing Reaction Products Activation energy Activation energy Reactants

92. Activation Energy The energy that is needed to get a reaction started

94. Enzymes Some chemical reactions are too slow or have activation energies that are too high to make them practical for living tissue. CATALYSTS. These chemical reactions are made possible by CATALYSTS.

95. Catalyst Substance that speeds up the rate of chemical reactions Work by lowering a reactions activation energy

96. Enzyme BIOLOGICAL CATALYSTS BIOLOGICAL CATALYSTS Speed up reactions in cells Very specific Named for the reaction it catylzes -ase Enzyme names always end in -ase

97. Reaction pathway without enzyme Activation energy without enzyme Activation energy with enzyme Reaction pathway with enzyme Reactants Products

98. Substrates The reactants of enzyme catalyzed reactions The active site of the enzyme and the substrate have complementary shapes Fit like a lock and key

99. Enzyme Action Enzyme – substrate complex

100. Glucose Substrates ATP Substrates bind to enzyme Substrates are converted into products Enzyme-substrate complex Enzyme (hexokinase) ADP Products Glucose-6- phosphate Products are released Active site

101. Regulation of Enzyme Activity Enzymes are affected by any variable that affects chemical reactions 1. pH 2. Temperature 3. Concentration of enzyme

103. 1. What happens to chemical bonds during chemical reactions Bonds are broken in reactants and new bonds are formed in products 2. Describe the role of energy in chemical reactions some chemical reactions release energy, and other chemical reactions absorb energy. Energy changes determine how easily a chemical reaction will occur

104. 3. What are enzymes, and how are they important to living things? Enzymes are biological catylasts. Cells use enzymes to speed up virtually every important chemical reaction that takes place in cells

105. 4. Describe how enzymes work, including the role of the enzyme substrate complex Substrates, the reactants of an enzyme-catylzed reaction, attach to the enzyme at an active site and form an enzyme – substrate complex. Once the complex is formed, the enzyme helps convert substrate into product

106. 5. A change in pH can change the protein. How might a change in pH affect the function of an enzyme such as hexokinase (hint: think about the analogy of the lock and key) A change in pH could change the shape of hexokinase. This change would diminish the ability of glucose and ATP to bind to the active site of the enzyme.

107. TEST TIME