1. 1 Macromolecule class #1: Polysaccharides Monomer = sugars Sugars = small carbohydrate molecules Carbohydrates ~= C n H 2n O n Contain one C=O group and many –OH’s Can contain other functional groups as well (carboxyls, amines) Most common sugar and monomer is glucose

2. 2 Glucose, straight chain depictions With numbering C C Remember, always 4 bonds to carbon; Often even if not depicted Abbreviated

3. 3 anomeric carbon Handout 2-7Haworth view Fisher view Chair view

4. 4 1 2 3 4 5 67 8 9 10 11

5. 5 anomeric carbon Handout 2-7Haworth view Fisher view Chair view

6. 6 1 2 3 4 5 67 8 9

7. 7 anomeric carbon Handout 2-7Haworth view Fisher view Chair view

8. 8 beta-glucosealpha-glucose These two distinct molecules are 2 different “isomers” of glucose. These two are “steroisomers” differing only in 3-D structure.

9. 9 Ball and stick models of glucose

10. 10 Alpha glucose All the hydroxyls and the –CH2OH are sticking out equatorial Except for the hydroxyl on the anomeric carbon 1

11. 11 From Handout 2-7 2 5 3

12. 12 From Handout 2-7 4 1 5 3

13. 13 Flat ring (Haworth projection) just gives the relative positions of the H and OH at each carbon, one is “above” the other. But it does not tell the positions of the groups relative to the plane of the ring (up, down or out) Relationship between Haworth (flat ring) depiction and chair-form Handout 2-8

14. 14 Glucose chair http://www.scientificpsychic.com/fitness/glucosebdchair.gif

15. 15 Glucose Gray = C White = H Red = O Ring oxygen C6 (-CH 2 OH) C5 C1 hydroxyl Alpha or beta?

16. 16 Chair depictions (from Googling chair + glucose) Beta? Alpha? Chair flip If you could see my back..

17. 17 Building a polymer from glucose OH H Alpha

18. 18 Polymers are built by removing a molecule of water between them, known as dehydration, or condensation. R-OH + HO-R → R-O-R + HOH This process does not happen by itself Rather, like virtually all of the reactions in a cell, it requires the aid of a CATALYST Dimer formation

19. 19 AND: Polymers are broken down by the reverse process, ADDING a molecule of water between them, known as HYDROLYSIS R-O-R + HOH→ R-OH + HO-R Here, dimer hydrolysis This process does not happen by itself Rather, like virtually all of the reactions in a cell, it requires the aid of a CATALYST

20. 20 Building a polymer from glucose OH H Alpha

21. 21 +

22. 22 Glycosidic bond Anomeric carbon is always one partner Beta conformation is now locked in here And ring is locked as a ring (loss of an H is necessary for rxn.) But not here Gycosidic bond here is equatorial-to-equatorial

23. 23 One is forced to draw strange “elbows” when depicting disaccharides using the Haworth projections (Here the C1 OH is “above” and the C4 OH is “below” (the H atom) Whereas we just saw in actuality that they are both equatorial in beta glucose)

24. 24 or glycogen chain down out H H Cellulose Tinker toys Polysaccharide formation

25. 25 Cellulose 3 6 3 6

26. 26 or glycogen chain down out H H Cellulose More glucoses

27. 27 4-1 6-1 4-1 Branches at carbon 6 hydroxyl Branching  compact structure Starch or glycogen granules, A storage form of glucose for energy Branching in starch C6

28. 28 Nucleus Cytoplasm Organelles Starch granules

29. 29 So: structure FUNCTION

30. 30 anomeric carbon a-glucose fructose ribose Handout 2-6 5-membered ring works too

31. 31 C2 glucosegalactosemannose C4 What’s different from glucose here? Examples of other hexoses allose

32. 32 More sugars: Mannose C 6 H 12 O 6 (different arrangement of OH’s and H’s) Galactose C 6 H 12 O 6 (different arrangement of OH’s and H’s) Deoxyribose C 5 H 10 O 5 (like ribose but one OH substituted by an H) More disaccharides (These do not go further to become polysaccharides): Lactose = glucose + galactose (milk sugar) Sucrose = fructose + glucose (table sugar, cane sugar)

33. 33 (Insect exoskeleton) (Bacterial cell walls) Metabolic intermediate

34. 34 Lipids Soluble in organic solvents (like octane, a hydrocarbon) (so “operationally” defined) Heterogeneous class of structures Not very polymer-like (in terms of covalently bonded structures)

35. 35 A steroid (Abbreviation convention: Always 4 bonds to carbon. Bonds to H not shown.) Really a small molecule

36. 36 hormone co-factor, vitamin Membrane component http://www.fas.org/irp/imint/docs/rst/Sect20/steroids.gif H2CH2C

37. 37 A fatty acid Fats

38. 38 A trigyceride (fat) Ester (functional group, acid + alcohol) Handout 2-9 top

39. 39 trans cis Solid fats Oils Effect of fatty acid structure on physical properties Free rotation about single bonds No free rotation about double bonds trans

40. 40 Fat globule Nucleus Adipocyte (fat storage cell)

41. 41 | NH 2 Note error on handout R=H: a phosphoester (phosphoric acid + alcohol) If R = H, “phosphatidic acid” Handout 2-9 F.A.s can be of different sizes

42. 42 [HO] Handout 2-9

43. 43 R=another alcohol: A phospho-diester HO Handout 2-9 HO –CH 2 CH 2 N + H 3 (alcohol = ethanolamine)

44. 44 HOH Phosphate head 2 fatty acid tails each Biological membranes are phospholipid bilayers

45. 45 Incidentally, note the functional groups we have met so far: Hydroxyl Amine Amide Carboxyl Carbonyl Aldehyde Ketone Ester:Carboxylic acid ester Phosphoester And: Glycosidic bonds C=C double bonds (cis and trans)

46. 46 Amino acids (the monomer of proteins) PROTEINS R

47. 47 At pH 7,,most amino acids are zwitterions (charged but electrically neutral)

48. 48 Equilibrium state of the carboxyl group lies far towards the ionized molecule at pH7

49. 49 +OH - ( -H + ) +H + Net charge 50-50 charged-uncharged at ~ pH9 (=the pK) 50-50 charged-uncharged at ~ pH2.5 (=the pK)

50. 50 Numbering (lettering) amino acids Alpha-carbon Alpha-carboxyl (attached to the α-carbon) Alpha-amino β γ δ ε ε-amino group lysine

51. 51 Shown uncharged (as on exams)

52. 52

53. 53 Amino acids in 3 dimensions See ball and stick model Asymmetric carbon (4 different groups attached) Stereoisomers Rotate polarized light Optical isomers Non-superimposable Mirror images L and D forms From Purves text

54. 54 Mannose coming out at you going behind the screen

55. 55 Condensation of amino acids to form a polypeptide (must be catalyzed)

56. 56 Parts of a polypeptide chain

57. 57 Without showing the R-groups: The backbone is monotonous. It is the side chains that provide the variety Handout 3-3

58. 58 “Polypeptides” vs. “proteins” Polypeptide = amino acids connected in a linear chain (polymer) Protein = a polypeptide or several associated polypeptides (discussed later) Often used synonymously Peptide (as opposed to polypeptide) is smaller, even 2 AAs (dipeptide)