1. Copyright © 2013 Pearson Education, Inc. Lectures prepared by Christine L. Case © 2013 Pearson Education, Inc. Lectures prepared by Christine L. Case Chemical Principles Chapter 2

2. © 2013 Pearson Education, Inc. Insert Fig CO 2

3. © 2013 Pearson Education, Inc. The Structure of Atoms  Chemistry is the study of interactions between atoms and molecules  The atom is the smallest unit of matter that enters into chemical reactions  Atoms interact to form molecules

4. © 2013 Pearson Education, Inc. The Structure of Atoms  Atoms are composed of  Electrons: negatively charged particles  Protons: positively charged particles  Neutrons: uncharged particles

5. © 2013 Pearson Education, Inc. The Structure of Atoms  Protons and neutrons are in the nucleus  Electrons move around the nucleus

6. © 2013 Pearson Education, Inc. Insert Fig 2.1 Figure 2.1 The structure of an atom.. Electron shells Nucleus Electron (e − ) Neutron (n 0 ) Proton (p + )

7. © 2013 Pearson Education, Inc.  Each chemical element has a different number of protons  Isotopes of an element are atoms with different numbers of neutrons. Isotopes of oxygen: Chemical Elements

8. © 2013 Pearson Education, Inc. Electronic Configurations  Electrons are arranged in electron shells corresponding to different energy levels

9. © 2013 Pearson Education, Inc. Insert Table 2.1 Table 2.1 The Elements of Life

10. © 2013 Pearson Education, Inc. How Atoms Form Molecules  Atoms combine to complete the outermost shell  The number of missing or extra electrons in this shell is known as the valence  Molecules hold together because the valence electrons of the combining atoms form attractive forces, called chemical bonds, between the atomic nuclei

11. © 2013 Pearson Education, Inc. Chemical Bonds  A compound contains different kinds of atoms H 2 O

12. © 2013 Pearson Education, Inc. Ionic Bonds  The number of protons and electrons is equal in an atom  Ions are charged atoms that have gained or lost electrons

13. © 2013 Pearson Education, Inc. Figure 2.2a Ionic bond formation. A sodium atom (Na) loses one electron to an electron acceptor and forms a sodium ion (Na + ). A chlorine atom (Cl) accepts one electron from an electron donor to become a chloride ion (Cl – ). Sodium ion (Na + ) Sodium atom (electron donor) Chlorine atom (electron acceptor) Chloride ion (Cl – ) Loss of electron Gain of electron

14. © 2013 Pearson Education, Inc. Ionic Bonds  Ionic bonds are attractions between ions of opposite charge  One atom loses electrons, and another gains electrons

15. © 2013 Pearson Education, Inc. Insert Fig 2.2b Figure 2.2b Ionic bond formation. The sodium and chloride ions are attracted because of their opposite charges and are held together by an ionic bond to form a molecule of sodium chloride. Chloride ion (Cl–) Sodium ion (Na + ) Sodium chloride molecule Na + Cl – NaCl

16. © 2013 Pearson Education, Inc. Covalent Bonds  Covalent bonds form when two atoms share one or more pairs of electrons

17. © 2013 Pearson Education, Inc. Insert Fig 2.3a Figure 2.3a Covalent bond formation. Diagram of Atomic Structure Structural Formula Molecular Formula A single covalent bond between two hydrogen atoms. Hydrogen atom Hydrogen molecule or

18. © 2013 Pearson Education, Inc. Insert Fig 2.3b Figure 2.3b Covalent bond formation. Diagram of Atomic Structure Structural Formula Molecular Formula Carbon atom Hydrogen atoms Methane molecule or Single covalent bonds between four hydrogen atoms and a carbon atom, forming a methane molecule.

19. © 2013 Pearson Education, Inc. Hydrogen Bonds  Hydrogen bonds form when a hydrogen atom that is covalently bonded to an O or N atom is attracted to another N or O atom in another molecule

20. © 2013 Pearson Education, Inc. Insert Fig 2.4b Figure 2.4b Hydrogen bond formation in water. Hydrogen bond

21. © 2013 Pearson Education, Inc. H 2 O 2H= 2  1= 2 O = 16 MW= 18 1 mole weighs 18 g Molecular Weight and Moles  The sum of the atomic weights in a molecule is the molecular weight  One mole of a substance is its molecular weight in grams

22. © 2013 Pearson Education, Inc. Chemical Reactions  Chemical reactions involve the making or breaking of bonds between atoms  A change in chemical energy occurs during a chemical reaction  Endergonic reactions absorb energy  Exergonic reactions release energy

23. © 2013 Pearson Education, Inc.  Occur when atoms, ions, or molecules combine to form new, larger molecules  Anabolism is the synthesis of molecules in a cell Synthesis Reactions A+BAB Atom, ion, or molecule A Atom, ion, or molecule B New molecule AB Combines to form

24. © 2013 Pearson Education, Inc.  Occur when a molecule is split into smaller molecules, ions, or atoms  Catabolism is the decomposition reactions in a cell Decomposition Reactions A+B AB Atom, ion, or molecule A Atom, ion, or molecule B New molecule AB Breaks down into

25. © 2013 Pearson Education, Inc. Exchange Reactions  Are part synthesis and part decomposition NaCl+H2OH2ONaOH+HCl

26. © 2013 Pearson Education, Inc. Reversible Reactions  Can readily go in either direction  Each direction may need special conditions A+B Water AB Heat

27. © 2013 Pearson Education, Inc. Important Biological Molecules  Organic compounds always contain carbon and hydrogen  Inorganic compounds typically lack carbon

28. © 2013 Pearson Education, Inc. Water  Inorganic  Polar molecule  Solvent  Polar substances dissociate, forming solutes

29. © 2013 Pearson Education, Inc. Insert Fig 2.4a Figure 2.4a Hydrogen bond formation in water.

30. © 2013 Pearson Education, Inc. Insert Fig 2.5 Figure 2.5 How water acts as a solvent for sodium chloride (NaCl). Sodium chloride crystal Sodium ion dissolved in water Chloride ion dissolved in water

31. © 2013 Pearson Education, Inc.  H + and OH − participate in chemical reactions R—R + H 2 O  R—OH + H—R Maltose + H 2 O  Glucose + Glucose Water

32. © 2013 Pearson Education, Inc. Maltose + H 2 O  Glucose + Glucose Glucose C 6 H 12 O 6 Glucose+C 6 H 12 O 6 Total C 12 H 24 O 12 Maltose C 12 H 22 O 11 The difference is: Water

33. © 2013 Pearson Education, Inc. Water  H bonds absorb heat  Makes water a temperature buffer

34. © 2013 Pearson Education, Inc. Insert Fig 2.4b Figure 2.4b Hydrogen bond formation in water. Hydrogen bond

35. © 2013 Pearson Education, Inc. Insert Fig 2.6 Figure 2.6 Acids, bases, and salts. AcidBase Salt HClNaClNaOH

36. © 2013 Pearson Education, Inc. Acids  Substances that dissociate into one or more H + HCl  H + + Cl −

37. © 2013 Pearson Education, Inc. Insert Fig 2.6a Figure 2.6a Acids, bases, and salts. Acid HCl

38. © 2013 Pearson Education, Inc. Bases  Substances that dissociate into one or more OH − NaOH  Na + + OH −

39. © 2013 Pearson Education, Inc. Insert Fig 2.6b Figure 2.6b Acids, bases, and salts. Base NaOH

40. © 2013 Pearson Education, Inc. Salts  Substances that dissociate into cations and anions, neither of which is H + or OH − NaCl  Na + + Cl −

41. © 2013 Pearson Education, Inc. Insert Fig 2.6c Figure 2.6c Acids, bases, and salts. Salt NaCl

42. © 2013 Pearson Education, Inc. Acid-Base Balance  The amount of H + in a solution is expressed as pH  pH =  log[H + ]  Increasing [H + ] increases acidity  Increasing [OH − ] increases alkalinity  Most organisms grow best between pH 6.5 and 8.5

43. © 2013 Pearson Education, Inc. Insert Fig 2.7 Figure 2.7 The pH scale. pH scale Stomach acid Lemon juice Grapefruit juice Wine Tomato juice Urine Milk Pure water Seawater Milk of magnesia Household ammonia Household bleach Oven cleaner Limewater Basic solution Neutral solution Acidic solution Human blood

44. © 2013 Pearson Education, Inc.  The chain of carbon atoms in an organic molecule is the carbon skeleton Structure and Chemistry

45. © 2013 Pearson Education, Inc.  Functional groups are responsible for most of the chemical properties of a particular organic compound Structure and Chemistry

46. © 2013 Pearson Education, Inc.

47. Insert Table 2.4 (two slides if possible) Table 2.4 Representative Functional Groups and the Compounds in Which They Are Found (Part 1 of 2)

48. © 2013 Pearson Education, Inc. Insert Table 2.4 (two slides if possible) Table 2.4 Representative Functional Groups and the Compounds in Which They Are Found (Part 2 of 2)

49. © 2013 Pearson Education, Inc.  Identify the functional groups in an amino acid Functional Groups

50. © 2013 Pearson Education, Inc.

51. Organic Compounds  Small organic molecules can combine into large macromolecules  Macromolecules are polymers consisting of many small repeating molecules  The smaller molecules are called monomers

52. © 2013 Pearson Education, Inc.  Monomers join by dehydration synthesis or condensation reactions Polymers

53. © 2013 Pearson Education, Inc.

54. Carbohydrates  Cell structures and energy sources  Consist of C, H, and O with the formula (CH 2 O) n  Monosaccharides are simple sugars with three to seven carbon atoms

55. © 2013 Pearson Education, Inc. Carbohydrates  Disaccharides are formed when two monosaccharides are joined in a dehydration synthesis  Disaccharides can be broken down by hydrolysis

56. © 2013 Pearson Education, Inc. Insert Fig 2.8 Figure 2.8 Dehydration synthesis and hydrolysis. Glucose C 6 H 12 O 6 Fructose C 6 H 12 O 6 Dehydration synthesis Hydrolysis Sucrose C 12 H 22 O 11 Water

57. © 2013 Pearson Education, Inc. Carbohydrates  Oligosaccharides consist of 2 to 20 monosaccharides  Polysaccharides consist of tens or hundreds of monosaccharides joined through dehydration synthesis  Starch, glycogen, dextran, and cellulose are polymers of glucose that are covalently bonded differently  Chitin is a polymer of two sugars repeating many times

58. © 2013 Pearson Education, Inc. Lipids  Primary components of cell membranes  Consist of C, H, and O  Are nonpolar and insoluble in water

59. © 2013 Pearson Education, Inc. Simple Lipids  Fats or triglycerides  Contain glycerol and fatty acids; formed by dehydration synthesis

60. © 2013 Pearson Education, Inc. Ester linkage Molecule of fat (triglyceride) Figure 2.9c Structural formulas of simple lipids. Palmitic acid (C 15 H 31 COOH) + (saturated) H2OH2O H2OH2O Stearic acid (C 17 H 35 COOH) + (saturated) cis configuration Oleic acid (C 17 H 33 COOH) + (unsaturated) H2OH2O Molecule of fat (triglyceride)

61. © 2013 Pearson Education, Inc. Simple Lipids  Saturated fat: no double bonds  Unsaturated fat: one or more double bonds in the fatty acids  Cis: H atoms on the same side of the double bond  Trans: H atoms on opposite sides of the double bond

62. © 2013 Pearson Education, Inc. Insert Fig 2.9c Palmitic acid (C 15 H 31 COOH) + (saturated) Ester linkage Molecule of fat (triglyceride) H2OH2O H2OH2O Stearic acid (C 17 H 35 COOH) + (saturated) cis configuration Oleic acid (C 17 H 33 COOH) + (unsaturated) H2OH2O Figure 2.9c Structural formulas of simple lipids.

63. © 2013 Pearson Education, Inc. Complex Lipids  Contain C, H, and O + P, N, or S  Membranes are made of phospholipids

64. © 2013 Pearson Education, Inc. Insert Fig 2.9a Carboxyl group Hydrocarbon chain Glycerol Fatty acid (palmitic acid), C 15 H 31 COOH Figure 2.9ab Structural formulas of simple lipids.

65. © 2013 Pearson Education, Inc. Steroids  Four carbon rings with an –OH group attached to one ring  Part of membranes

66. © 2013 Pearson Education, Inc. Insert Fig 2.11 Figure 2.11 Cholesterol, a steroid.

67. © 2013 Pearson Education, Inc. Proteins  Are essential in cell structure and function  Enzymes are proteins that speed chemical reactions  Transporter proteins move chemicals across membranes  Flagella are made of proteins  Some bacterial toxins are proteins

68. © 2013 Pearson Education, Inc. Amino Acids  Proteins consist of subunits called amino acids

69. © 2013 Pearson Education, Inc. Insert Fig 2.12 Figure 2.12 Amino acid structure. Side group Amino group Carboxyl group Generalized amino acid Cyclic side group Tyrosine

70. © 2013 Pearson Education, Inc. Amino Acids  Exist in either of two stereoisomers: D or L  L -forms are most often found in nature

71. © 2013 Pearson Education, Inc. Insert Fig 2.13 Figure 2.13 The L- and D-isomers of an amino acid, shown with ball-and-stick models. L-amino acidD-amino acid Left hand Right hand Mirror

72. © 2013 Pearson Education, Inc. Peptide Bonds  Peptide bonds between amino acids are formed by dehydration synthesis

73. © 2013 Pearson Education, Inc. Insert Fig 2.14 Figure 2.14 Peptide bond formation by dehydration synthesis. Glycine Alanine Dehydration synthesis Peptide bond Glycylalanine (a dipeptide) Water

74. © 2013 Pearson Education, Inc. Levels of Protein Structure  The primary structure is a polypeptide chain

75. © 2013 Pearson Education, Inc. Peptide bonds Figure 2.15a Protein structure. (a) Primary structure: polypeptide strand

76. © 2013 Pearson Education, Inc. Levels of Protein Structure  The secondary structure occurs when the amino acid chain folds and coils in a regular helix or pleats

77. © 2013 Pearson Education, Inc. Insert Fig 2.15b Hydrogen bond (b) Secondary structure: helix and pleated sheets (with three polypeptide strands) Helix Pleated sheet Disulfide bridge Figure 2.15b Protein structure.

78. © 2013 Pearson Education, Inc. Levels of Protein Structure  The tertiary structure occurs when the helix folds irregularly, forming disulfide bridges, hydrogen bonds, and ionic bonds between amino acids in the chain

79. © 2013 Pearson Education, Inc. Insert Fig 2.15c (c) Tertiary structure: folded helix and pleated sheet Hydrogen bond Disulfide bridge (between cysteine molecules) Ionic bond Details of bonds associated with tertiary structure Hydrophobic interaction Polypeptide strand Figure 2.15c Protein structure.

80. © 2013 Pearson Education, Inc. Levels of Protein Structure  The quaternary structure consists of two or more polypeptides

81. © 2013 Pearson Education, Inc. Insert Fig 2.15d (d) Quaternary structure: two or more polypeptides in their folded states Figure 2.15d Protein structure.

82. © 2013 Pearson Education, Inc. Insert Fig 2.15Insert Fig 2.15a Peptide bonds (a) Primary structure: polypeptide strand Hydrogen bond (b) Secondary structure: helix and pleated sheets (with three polypeptide strands) Helix Pleated sheet Disulfide bridge (c) Tertiary structure: folded helix and pleated sheet (d) Quaternary structure: two or more polypeptides in their folded states Hydrogen bond Disulfide bridge (between cysteine molecules) Ionic bond Details of bonds associated with tertiary structure Hydrophobic interaction Polypeptide strand Figure 2.15 Protein structure.

83. © 2013 Pearson Education, Inc. Levels of Protein Structure  Conjugated proteins consist of amino acids and other organic molecules  Glycoproteins  Nucleoproteins  Lipoproteins

84. © 2013 Pearson Education, Inc. Nucleic Acids  Consist of nucleotides  Nucleotides consist of  Pentose  Phosphate group  Nitrogen-containing (purine or pyrimidine) base  Nucleosides consist of  Pentose  Nitrogen-containing base

85. © 2013 Pearson Education, Inc. DNA  Deoxyribonucleic acid  Has deoxyribose  Exists as a double helix  A hydrogen bonds with T  C hydrogen bonds with G

86. © 2013 Pearson Education, Inc. Insert Fig 2.16 Figure 2.16 The Structure of DNA. PhosphateSugar Adenine (A)Thymine (T)Sugar Phosphate Adenine nucleotide The carbon atoms in the sugars are identified by adding a marker, ’ (for example, 5’, pronounced “5-prime”). This differentiates them from the carbon atoms in the nucleo- bases, such as Thymine. Adenine and Thymine (as well as Cytosine and Guanine, not shown here) are nitrogenous bases or nucleobases. Hydrogen bonds Individual DNA nucleotides are composed of a deoxyribose sugar molecule covalently bonded to a phosphate group at the 5’ carbon, and to a nitrogen-containing base at the 3’ carbon. The two nucleotides shown here are held together by hydrogen bonds. Sugars Phosphates Sugar-phosphate backbone The sugar-phosphate backbone of one strand is upside down, or antiparallel, relative to the backbone of the other strand. DNA double helix DNA’s double-helical, ladder- like form is made up of many nucleotides base pairs forming the rungs, and the repeating sugar-phosphate combination, forming the backbone. Thymine nucleotide

87. © 2013 Pearson Education, Inc. RNA  Ribonucleic acid  Has ribose  Is single-stranded

88. © 2013 Pearson Education, Inc. Insert Fig 2.17 Figure 2.17 A uracil nucleotide of RNA. Phosphate Uracil (U) Ribose

89. © 2013 Pearson Education, Inc.  Adenosine triphosphate  Has ribose, adenine, and three phosphate groups ATP

90. © 2013 Pearson Education, Inc. Insert Fig 2.18 Figure 2.18 The structure of ATP. Phosphates Adenosine Ribose Adenine

91. © 2013 Pearson Education, Inc.  Is made by dehydration synthesis  Is broken by hydrolysis to liberate useful energy for the cell ATP

92. © 2013 Pearson Education, Inc.