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CARBON AND THE MOLECULAR DIVERSITY OF LIFE

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Presentation on theme: "CARBON AND THE MOLECULAR DIVERSITY OF LIFE"— Presentation transcript:

1 CARBON AND THE MOLECULAR DIVERSITY OF LIFE
CHAPTER 4

2 ISOMERS FUNCTIONAL GROUPS
Compounds with the same chemical formula but different structures FUNCTIONAL GROUPS See diagram of functional groups

3 Figure 4.6 Three types of isomers

4 Figure 4.6ax Structural isomers

5 Table 4.1 Functional Groups of Organic Compounds

6 Figure 4.8 A comparison of functional groups of female (estradiol) and male (testosterone) sex hormones

7 Figure 4.8x1 Estrone and testosterone

8

9 THE STRUCTURE AND FUNCTION OF MACROMOLECULES
CHAPTER 5

10 SYNTHESIS AND BREAKDOWN
Dehydration synthesis (condensation reaction) – removal of water to join 2 compounds Hydrolysis – addition of water to break a bond between 2 compounds

11 Figure 5.2 The synthesis and breakdown of polymers

12 CARBOHYDRATES Monosaccharides
Examples: glucose, fructose, and galactose One sugar Disaccharides Examples: Lactose, sucrose and maltose Two sugars Joined by glycosidic linkage via dehydration synthesis Polysaccharides Examples: starch, glycogen, and cellulose Many sugars

13 Figure 5.3 The structure and classification of some monosaccharides

14 Figure 5.4 Linear and ring forms of glucose

15 Figure 5.5 Examples of disaccharide synthesis

16 Figure 5.6 Storage polysaccharides

17 Figure 5.7a Starch and cellulose structures

18 Figure 5.7b,c Starch and cellulose structures

19 Figure 5.8 The arrangement of cellulose in plant cell walls

20 Figure 5.x1 Cellulose digestion: termite and Trichonympha

21 Figure 5.x2 Cellulose digestion: cow

22 Figure 5.9 Chitin, a structural polysaccharide: exoskeleton and surgical thread

23 LIPIDS Little or no affinity for water (hydrophobic)
Examples: Fat, phospholipids, and steroids Fats – composed of glycerol (an alcohol) and fatty acids Saturated – no double bonds in carbon chain Unsaturated – at least one double bond in carbon chain

24 Figure 5.11 Examples of saturated and unsaturated fats and fatty acids

25 Figure 5.11x Saturated and unsaturated fats and fatty acids: butter and oil

26 Figure 5.12 The structure of a phospholipid

27 Figure 5.13 Two structures formed by self-assembly of phospholipids in aqueous environments   

28 Figure 5.10 The synthesis and structure of a fat, or triacylglycerol

29 Figure 5.14 Cholesterol, a steroid

30 Figure 5.14x Cholesterol    

31 Table 5.1 An Overview of Protein Functions

32 PROTEIN Polypeptide – polymer of amino acids
There are 20 different amino acids differing only by the R group

33

34 Figure 5.15 The 20 amino acids of proteins: nonpolar

35 Figure 5.15 The 20 amino acids of proteins: polar and electrically charged

36 Figure 5.16 Making a polypeptide chain

37 FOUR LEVELS OF PROTEIN STRUCTURE
Primary – sequences of amino acids Secondary – hydrogen bonds cause coils and folds Pleated sheet and alpha helix Tertiary – irregular contortions due to various weak bonds: Hydrophobic interactions Disulfide bridges Ionic bonds Van der Waals interactions Quaternary – two or more polypeptide chains aggregated into one functional macromolecule Examples: collagen and hemoglobin

38 Figure 5.18 The primary structure of a protein

39 Figure 5.19 A single amino acid substitution in a protein causes sickle-cell disease

40 Figure 5.19x Sickled cells

41 Figure 5.20 The secondary structure of a protein

42 Figure 5.22 Examples of interactions contributing to the tertiary structure of a protein

43 Figure 5.23 The quaternary structure of proteins

44 Figure 5.24 Review: the four levels of protein structure

45 Figure 5.25 Denaturation and renaturation of a protein

46 Figure 5.21 Spider silk: a structural protein

47 Figure 5.21x Silk drawn from the spinnerets at the rear of a spider

48 NUCLEIC ACIDS Examples: DNA and RNA
We will discuss these in great detail later in the semester! 

49 Figure 5.29 The components of nucleic acids

50 Figure 5.30 The DNA double helix and its replication

51 AN INTRODUCTION TO METABOLISM
CHAPTER 8

52 Figure 6.2 Transformations between kinetic and potential energy

53 Figure 6.2x1 Kinetic and potential energy: dam

54 Figure 6.2x2 Kinetic and potential energy: cheetah at rest and running

55 THERMODYNAMICS First Law of Thermodynamics – energy can be transferred and transformed, but not created nor destroyed Second Law of Thermodynamics – every energy transfer or transformation makes the universe more disordered (have more entropy)

56 Entropy – measure of disorder or randomness
Most energy transformations involve at least some energy be changed to heat Heat is the lowest form of energy Biological order has increased over time Second law requires only that processes increase the entropy of the universe Organisms may decrease entropy but entire universe must increase entropy

57 Figure 6.4 Order as a characteristic of life

58 Free energy (G) – energy available to do work when temperature is uniform throughout system
G = H – TS H = system’s total energy (enthalpy) T = temp in Kelvin (° C + 273) S = entropy

59 ∆ G = G final state – G starting state
∆ G = ∆ H - T∆ S For a spontaneous reaction: ∆ G = negative So must: give up energy (decrease H) and/or give up order (increase S) ∆ G = 0 at equilibrium Free energy increases if move away from equilibrium and decreases if move toward equilibrium

60 Figure 6.5 The relationship of free energy to stability, work capacity, and spontaneous change

61 Exergonic ∆ G = negative Spontaneous Net release of energy Endergonic ∆ G = positive NOT spontaneous Stores free energy in molecules

62 Figure 6.6 Energy changes in exergonic and endergonic reactions

63 Cells at equilibrium are dead!
Cells can keep disequilibrium by having products of one reaction not accumulate but instead become reactants of another reaction Energy coupling – an exergoinc reaction drives an endergoinc reaction

64 Figure 6.7 Disequilibrium and work in closed and open systems

65 ATP = ADENOSINE TRIPHOSPHATE
ATP + H2O ADP + Pi ∆ G = -7.3kcal/mol ADP = adenosine diphosphate Normally the phosphate is bonded to an intermediate compound which is then considered phosphorylated The reverse reaction is endergonic and requires +7.3 kcal/mol to make ATP from ADP

66 Figure 6.8 The structure and hydrolysis of ATP

67 Figure 6.9 Energy coupling by phosphate transfer

68 Figure The ATP cycle

69 ENZYMES Catalytic proteins or enzymes – change the rate of reaction without being consumed by the reaction Activation energy (EA) – energy needed to start a reaction Energy needed to contort the reactants so the bonds can change Enzymes lower activation energy by enabling reactants to absorb enough energy to reach transition state at moderate temps

70 Enzymes are substrate specific
Substrate – the reactant on which an enzyme works Active site – area on enzyme where substrate fits Induced fit – model of enzyme activity

71 Figure 6.12 Energy profile of an exergonic reaction

72 Figure 6.14 The induced fit between an enzyme and its substrate

73 Figure 6.15 The catalytic cycle of an enzyme

74 Effects of pH and Temp Optimal temperatures and pH ranges exist for enzymes

75 Figure 6.16 Environmental factors affecting enzyme activity

76 Cofactors – non-protein helpers that bind to active site or substrate (zinc, iron)
Coenzymes – cofactors that are organic (vitamins) Enzyme Inhibitors – reduce enzyme activity Competitive inhibitors – block substrate from entering active site Reversible Overcome by adding more substrate Noncompetitive inhibitors – bind to another part of enzyme thereby changing the enzyme’s shape making it inactive Irreversible Examples: DDT, sarin gas, and penicillin

77 Figure 6.17 Inhibition of enzyme activity

78 Allosteric regulation
Allosteric sites – receptors on enzymes (not the active site) that may either inhibit or stimulate enzyme activity Feedback inhibition End product of a pathway acts as a inhibitor of an enzyme within the pathway Cooperativity – an enzyme with multiple subunits where binding to one active site causes shape changes to rest of subunits which in turn activates those subunits

79 Figure 6.18 Allosteric regulation of enzyme activity

80 Figure 6.19 Feedback inhibition

81 Figure Cooperativity


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