Molecules of Life. Chapter 22. Great Idea: A cell s major parts are constructed from a few simple molecular building blocks 1

Transcription

1 Molecules of Life Chapter 22 Great Idea: A cell s major parts are constructed from a few simple molecular building blocks 1

2 Chapter Outline Organic Molecules Organic Chemistry Proteins: The Workhorses of Life Carbohydrates Lipids Minerals and Vitamins 2

3 Organic Molecules 3

4 Four Basic Characteristics Most molecules based on chemistry of carbon Organic molecules Life s molecules form from few elements H, O, C, N 97.5% of body weight Molecules composed of simple building blocks Arranged differently Shape determines behavior Determines ability for bonding 4

5 Chemical Shorthand No H atoms or bonds to H are shown C atoms are not shown explicitly Shorthand 5

6 iclicker Question Most molecules in living systems are based on the chemistry of: A nitrogen B carbon C phosphorus D sodium 6

7 iclicker Question Which four elements comprise 97.5% of our bodies weight? A P, S, Ca and Mg B Fe, H, O, Na C H, O, C, N 7

8 8

9 Remember Abundance of Elements in Solar System C Relative Abundance of Elements in the Sun Log of Relative Abundance H He Li Be C O Ne Mg Fe Si S N Ar Ca Al Na P Cl K Fe B Atomic Number 9

10 Recall Covalent Bonds and Carbon C is a special case C - C C C C C C Valence electrons for C are four (one in each orbit of the 2 nd shell) C C: single covalent bond (one orbit; two atoms) C C C: two covalent bonds; two orbits; three atoms 10

11 11

12 Principles of Carbon Chemistry: Functional Groups Features of C macromolecules Carbon skeleton (chains, branches, rings) Groups of atoms attached to carbon skeleton - functional groups Hydroxyl (OH) Amino (NH 2 ) Phosphate (P) C C C OH C 12

13 Principle of Polymers Small molecules joined together to form large molecules up to 1,000 s of carbon atoms (macromolecules) Array of combinations, each with its own unique chemistry Principle of hierarchy theory and emergent properties 13

14 Simple to Complex Polymers of Carbon Methane - 1 C atom Ethane 2 C atoms Fullerene 60 + C atoms (Buckyballs) 14

15 Complex Carbon Polymers nicotene caffeine aspirin Taxol chemotherapy drug 15

16 Hierarchy Theory and Emergent Properties Number of macromolecules, each with its own chemistry Carbon Skeletons (e.g., branch, chains, etc. Functional Groups (e.g., OH, NH2, etc.) Carbon Atoms 16

17 Principle of Polymers In living systems, polymers of carbon result in four major classes of macromolecules Carbohydrates Proteins Nucleic acids Lipids Potential diversity of carbon polymers 17

18 Hydrocarbons Carbon compounds with only two elements (carbon and hydrogen) Most simple compound: methane (CH 4 ) H H C H H 18

19 Hydrocarbons: C to C Bonding C to C bond can be single bond (C-C) Ethane C to C bond can be double bond (C = C) Ethene or ethylene C to C bond can be triple bond (C = C) Ethyne Saturated/unsaturated 19

20 Hydrocarbons Alkanes (C C bonds only) Methane (C 1 H 4 ) Natural gas Ethane (C 2 H 6 ) Propane (C 3 H 8 ) Propane gas Butane (C 4 H 10 ) Pentane (C 5 H 12 ) Octane(C 8 H 18 ) Gasoline Decane(C 10 H 22 ) Pattern: C n H 2n + 2 ) Triple bond (C = C) Double bond (C = C) Aromatics (cyclic C atoms/aromatics) C 6 H 6 20

21 Aromatic Hydrocarbons 21

22 Question There are millions of organic compounds but only a few thousand inorganic compounds because? A. Organic compounds are formed by living critters B. There is more C on the Earth s surface than most other elements C. Atoms of elements other than C never combine with themselves D. C atoms combine with up to four other atoms, including other C atoms 22

23 Functionality of Hydrocarbons Carbon skeleton Functional groups (e.g., OH) 23

24 Organic and Biochemistry Keys: Structure of basic unit (monomer) Polymer structure (macromolecule) Functional group (e.g., OH, PO 3 or NH 2 ) Types of carbon polymers in living systems Carbohydrates Lipids Proteins Nucleic acids 24

25 Biochemistry Carbohydrates Monomer: monosaccharide (glucose or C 6 H 12 O 6 ) Polymer: polysaccharide Functional unit: hydroxyl or OH - Proteins Monomer: amino acid (peptide) Polymer: polypeptide and protein Functional unit: amine or NH 2 Nucleic Acids Monomer: nucleotide Polymer: polynucleotide - DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) Functional units: organic N base, carbohydrate, and phosphate Lipids Monomer: fatty acid + glycerol unit Polymer: fats, phospholipids and steroids Functional unit: glycerol (3 OH- groups) 25

26 iclicker Question Fatty acids and glycerols are part of A Carbohydrates B Proteins C Nucleic Acids D Lipids 26

27 iclicker Question The monomer monosaccharide is what type of molecular polymer? A Carbohydrate B Protein C Nucleic Acid D Lipid 27

28 iclicker Question Amino acids are portions of A Carbohydrates B Proteins C Nucleic Acids D Lipids 28

29 iclicker Question Nucleotides are portions of A Carbohydrate B Protein C Nucleic Acid D Lipid 29

30 Carbohydrates 30

31 Carbohydrates Structure C, H, O Simplest Sugars C n H 2n O n Monosaccharides Polysaccharide Starches Cellulose 31

32 32

33 Carbohydrates Keys Monosaccharide or Glucose (C 6 H 12 O 6 ) Functional unit: hydroxyl or OH- 33

34 Monosaccharides 34

35 Polysaccharide: Glycogen 35

36 iclicker Question True or False: Starch and cellulose are both polymers of glucose. A True B False 36

37 iclicker Question Individual sugar molecules are called: A glucoses B starches C monosaccharides 37

38 iclicker Question The general chemical formula for sugar is: A NaCl B C n H 2n O n C C n H 2n+2 D C 20 H 38 S 2 N 4 38

39 Proteins: The Workhorses of Life 39

40 Amino Acids: The Building Blocks of Proteins Amino Acid Carboxyl group Amino group Carbon atom Side group 40

41 Amino Acids: The Building Blocks of Proteins Side Group Makes amino acid unique 41

42 Amino Acids cont. Bonding Two amino acids H bonds with OH Forms H 2 O Forms peptide bond Polypeptide chain Protein Large molecule Chain of amino acids Only 20 amino acids in living organisms 42

43 The Structure of Proteins 43

44 Enzymes (protein catalysts) Enzymes Specific shape & structure Facilitates bonding 44

45 Enzymes 45

46 How Most Drugs Work Blocking enzymes Block active site Molecules cannot bond Reaction does not take place Shape of molecules Block membrane transport Block neurotransmitters 46

47 Proteins Keys Amino acid (monomer) Polypeptide (polymer) Functional unit: amine or NH 2 Polypeptide bond serine lysine arginine tryptophan glutamic acid etc. 47

48 Proteins: Linear Structure 48

49 Proteins: Linear Structure 49

50 Protein Conformation (1 and 2 nd ) 50

51 Protein Conformation (3 rd & 4 rd ) 51

52 52

53 53

54 iclicker Question Proteins are made up of strings of basic building blocks called: A amino acids B monosaccharides C nucleotides 54

55 iclicker Question How many different amino acids appear in the proteins of living systems on Earth? A 10 B 20 C 50 D

56 iclicker Question The exact sequence of amino acids that go into a protein is called its: A primary structure B secondary structure C tertiary structure D quaternary structure 56

57 iclicker Question In general, meat and dairy products supply low-quality proteins, while plant product supply high-quality proteins. A True B False 57

58 iclicker Question Of the 20 amino acids, how many are essential amino acids for human adults? A 8 B 12 C 17 D 20 58

59 iclicker Question Shapes taken by the string of amino acids of a protein, such as a long helix or a sphere, are called its: A primary structure B secondary structure C tertiary structure D quaternary structure 59

60 iclicker Question Silk, hair, and fingernails are made of: A proteins B lipids C carbohydrates 60

61 Nucleic Acids Keys Nucleotides Functional units: organic N base, carbohydrate, and phosphate 61

62 Nucleic Acids as Polymers: DNA Double Helix 62

63 63

64 Lipids 64

65 Lipids Lipids Insoluble in water Role of lipids Cell membranes Store energy Phospholipids Make up cell membrane 65

66 Saturated C is fully bonded Basis of cholesterol Unsaturated Monounsaturated Polyunsaturated hydrogenation Saturated and Unsaturated Fats 66

67 Cell Membranes Cell membrane Hydrophilic Hydrophobic 67

68 Biochemistry: Lipids Keys Fatty acids C Functional unit: glycerol (3 OH- groups) 68

69 Saturated Fats 69

70 Unsaturated Fats 70

71 iclicker Question Fatty acids and glycerols are part of A Carbohydrates B Proteins C Nucleic Acids D Lipids 71

72 iclicker Question Saturated fats have no double bonds. A True B False 72

73 iclicker Question The monomer monosaccharide is what type of molecular polymer? A Carbohydrate B Protein C Nucleic Acid D Lipid 73

74 iclicker Question Amino acids are portions of A Carbohydrates B Proteins C Nucleic Acids D Lipids 74

75 iclicker Question Nucleotides are portions of A Carbohydrate B Protein C Nucleic Acid D Lipid 75

76 Biochemistry Summary Carbohydrates Monomer: monosaccharide (glucose or C 6 H 12 O 6 ) Polymer: polysaccharide Functional unit: hydroxyl or OH - Proteins Monomer: amino acid (peptide) Polymer: polypeptide and protein Functional unit: amine or NH 2 Nucleic Acids Monomer: nucleotide Polymer: polynucleotide - DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) Functional units: organic N base, carbohydrate, and phosphate Lipids Monomer: fatty acid + glycerol unit Polymer: fats, phospholipids and steroids Functional unit: glycerol (3 OH- groups) 76

77 Carbon Metabolism Biosynthesis (Anabolism) CO 2 + H 2 O + Energy CH 2 O + O 2 (light) (C - C Bonds) Catabolism CH 2 O + O 2 CO 2 + H 2 O + Energy (C - C Bonds) (heat + chemical energy ATP) Key is the C-C covalent bonding, which in turn is determined by electrons in the valence state, which in turn is underpinned by energy of electrons in their respective shells (storage and processing of energy via the making and breaking of C-C bonds) 77

78 78

79 Granola Bar and the Carbon Atom The energy of a granola bar is a function of multiple excited electrons being kicked to a higher quantum level in a chlorophyll molecule; subsequently, that potential energy is snatched and stored chemically in a carbohydrate molecule. When you digest the carbohydrate polymer and break the covalent bonds, the potential energy of the electron in an elevated state is released as heat/chemical energy in metabolism. 79

80 iclicker Question The chemical reactivity of organic carbon compounds is a function of the reactivity of the. A Carbon to carbon double bond (C = C) B Carbon to carbon triple bond (C = C) C Carbon to carbon single bond (C C) D Functional groups bond to the carbon atom E Reactivity of the covalent bonds between carbon atoms 80

81 Hierarchy in Biochemistry Protein Polypeptide Amino Acid Carbon Skeleton + Amine group (NH 2 ) 81

82 Minerals and Vitamins 82

83 Minerals Minerals All chemical elements except C, H, N, O Example Calcium 2% of weight 83

84 Vitamins Vitamins Organic molecules Must be taken in with food Except vitamin D Water soluble Vitamins B & C Fat soluble Vitamins A, D, E, & K Function Assist enzymes 84

85 SUMMARY Carbon is unique in its chemistry Unusual behavior of carbon results in an huge array of simple to complex molecules Life as we know it is hard to imagine without carbon behaving as a polymer The chemistry of carbon is a case study of the principle of hierarchy theory and emergent properties Carbon metabolism is the currency by which energy is processed, stored and used Weak chemical bonds (covalent carbon bonds) play a critical role in the chemistry of life 85

86 iclicker Question Which vitamins are water soluble? A B and C B A, D, E, and K C F, G, and H 86

87 iclicker Question The information in this chapter influences me in terms of eating a healthier diet. A True B False 87