1. 1 anomeric carbon

2. 2

3. 3

4. 4 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

5. 5 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 (It is NOT like glucose ring formation) Rather, like virtually all of the reactions in a cell, it requires the aid of a CATALYST Dimer formation

6. 6 AND: Polymers are broken down by the reverse process, ADDING a molecule of water between them, known as DIMER HYDROLYSIS R-O-R + HOH→ R-OH + HO-R This process does not happen by itself Rather, like virtually all of the reaction in a cell, it requires the aid of a CATALYST

7. 7 Building a polymer from glucose

8. 8

9. 9 Glycosidic bond Anomeric carbon is always one partner Beta conformation is now locked in here But not here C4 = equatorial out (always in glucose) C1 = equatorial out (in beta glucose) The two glucose molecules are connected in a ~straight line in cellobose O H H H CHOH 2 HO H H 4 O H H H CHOH 2 HO OH HO H H 4 Beta-glucose residue “Beta”-glucose residue Cellobiose with right-hand glucose shown as beta

10. 10 Glycosidic bond Anomeric carbon is always one partner Alpha conformation of –OH is now locked in here But not here C4 = equatorial out (always in glucose) C1 = axial down (in alpha glucose) O H H H CHOH 2 HO H H 4 O H H H CHOH 2 HO OH HO H H 4 Alpha-glucose residue “Beta”-glucose residue Maltose with right-hand glucose shown as beta The two glucose molecules are connected with an angle between them in maltose

11. 11 One is forced to draw strange “elbows” when depicting disaccharides using the Haworth projections. Such elbows do not exist in reality. (here the C1 OH is “above” and the C4 OH is “below” Whereas we just saw in actuality that they are both equatorial in beta glucose) Equatorial bond is above the H Equatorial bond is below the H

12. 12 Tinker toys Starch or glycogen chain down out H H Cellulose Tinker toys

13. 13 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

14. 14 Nucleus Cytoplasm Organelles Starch granules

15. 15 or glycogen chain down out H H Cellulose

16. 16 Cellulose Cell wall of green algae

17. 17 anomeric carbon fructose ribose glucose From handout 2-6

18. 18 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 4 (like ribose but C2’s OH substituted by an H) More disaccharides Lactose = b-1-glucose to C4 of galactose (milk sugar) Sucrose = b-2-fructose to C1- a-1-glucose (table sugar, cane sugar)

19. 19 (Insect exoskeleton) (Bacterial cell walls) Metabolic intermediate

20. 20 Lipids Soluble in organic solvents (like octane, a hydrocarbon) Heterogeneous class of structures Not very polymer-like (in terms of covalently bonded structures)

21. 21 A steroid (Abbreviation convention: Always 4 bonds to carbon. Bonds to H not shown.)

22. 22 A fatty acid Fats

23. 23 A trigyceride (fat) Ester (functional group, acid + alcohol)

24. 24 trans cis trans cis Solid fats Oils Effect of fatty acid structure on physical properties

25. 25 Fat globule Nucleus Adipocyte (fat storage cell)

26. 26 | NH 2 Note error on handout R=H: a phosphoester (phosphoric acid + alcohol) In this case: phosphatidic acid Handout 2-10

27. 27 [HO] Handout 2-10

28. 28 R=another alcohol: A phospho-diester HO Handout 2-10 HO –CH 2 CH 2 N + H 3 (alcohol = ethanolamine)

29. 29 HOH Phosphate head 2 fatty acid tails each Biological membranes are phospholipid bilayers

30. 30 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)

31. 31 Amino acids (the monomer of proteins) PROTEINS

32. 32 At pH 7,,most amino acids are zwitterions (charged but electrically neutral)

33. 33

34. 34 +OH - ( -H + ) +H + Net charge 50-50 charged-uncharged at ~ pH9 (=the pK) 50-50 charged-uncharged at ~ pH2.5 (=the pK)

35. 35 Numbering (lettering) amino acids Alpha-carbon Alpha-carboxyl (attached to the α-carbon) Alpha-amino β γ δ ε ε-amino group

36. 36 Amino acid examples Molecular weights 75 – 203 (MW) Glycine (gly)Side chain = HSmallest (75) Aspartic acid (asp, aspartate)One – charge β-carboxyl: -CH 2 -COOH Tryptophan (trp)5+6 membered rings Hydrophobic, largest (203) Lysine (lys)One + chargeε-amino Alanine (ala)One carbon (methyl group) -CH3 Arginine (arg, guanido group) One + charge-(NH-C (NH 2 )NH 2 ) +,

37. 37

38. 38 Shown uncharged (as on exams)

39. 39

40. 40 Amino acids in 3 dimensions Asymmetric carbon (4 different groups attached) Stereoisomers Rotate polarized light Optical isomers Non-superimposable Mirror images L and D forms From Purves text

41. 41 Mannose

42. 42 Condensation of amino acids to form a polypeptide (must be catalyzed)

43. 43 Parts of a polypeptide chain

44. 44 Handout 3-3 (Without showing the R-groups) The backbone is monotonous It is the side chains that provide the variety The backbone is monotonous

45. 45 “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)