1. Macromolecules & Carbohydrates
Lecture 3
Dr. Mamoun Ahram

2. Cell's weight

3. Subunits
Subunits: the small building blocks (precursors) used to make macromolecules
Macromolecules: large molecules made of subunits

4. Macromolecules Carbohydrates (monosaccharides) Proteins (amino acids)
Nucleic acids (nucleotides)
Lipids (fatty acids)
Except for lipids, these macromolecules are also considered polymers

6. Relationship (monomers and polymers)

7. How water is removed?
Mechanism 1: One subunit contributes an “H” and the other subunit contributes an “OH”
Mechanism 2: One subunit contributes 2 “H” the other subunit contributes an “O”

8. Carbohydrates

9. What are they? Carbohydrates are polyhydroxy aldehydes or ketones
Saccharide is another name for a carbohydrate

10. Functions Source of energy Structure (cellulose and chitin)
Building blocks
Cellular recognition

11. Classification I Monosaccharides Disaccharides Oligosaccharides
Polysaccharides

12. Monosaccharides Basic chemical formula: (CH2O)n
They contain two or more hydroxyl groups

13. Drawing sugars Fisher projections or perspective structural formulas
Forward
Backward
Top (C1):
Most highly oxidized C

16. Numbering carbons…again

17. Classification 2
By the number of carbon atoms they contain

20. Trioses

21. Glyceraldehyde
Chiral carbon

22. Mirror images and non-superimposable, then…stereoisomers

24. Stereoisomers

25. This is different than structural isomers

26. Sugar enantiomers (D- vs. L-)

27. Which chiral carbon?

28. Number of possible stereoisomers
2n (n is the number of chiral carbons in a sugar molecule)

29. Isomers of glucose

30. Diastereomers

31. Epimers

32. Formation of a ring structure

33. Hemiacetal vs. hemiketal

34. Haworth vs. Fischer projections

35. Ring structures

36. Example

37. Anomers

38. - vs. -glucopyranose

39. Cyclic fructose

40. Galactose

41. Fischer vs. Haworth Left-right vs. up-down

42. Cyclic aldohexoses

43. Cyclic ribofuranose

44. Modified sugars

45. Sugar esters (esterification)
What is the reacting functional group? Where does it react? What are the end products? Where are they used?

46. Sugar acids (oxidation)
Where is it oxidized? What does it form?

47. Example 1

48. Example 2

49. Example 3

50. Note
Oxidation of ketoses to carboxylic acids does not occur

51. Sugar alcohols (reduction)
What does it form?
Examples include sorbitol, mannitol, and xylitol, which are used to sweeten food products

52. Deoxy sugars One or more hydroxyl groups are replaced by hydrogens
An example is 2-deoxy-2-ribose, which is a constituent of DNA

53. N-glycosides
What is the reacting functional group? Where does it react? What are the end products? Where are they used?
Examples: nucleotides (DNA and RNA)

54. Amino sugars
What is the reacting functional group? Where does it react? What are the end products? Where are they used?
Further modification by acetylation

55. O-Glycosides
What is the reacting functional group? Where does it react? What are the end products? Where are they used?

56. Formation of full acetal

57. Disaccharides
What are disaccharide? Oligosaccharides? Hetero- vs. homo-?
What is the type of reaction?
What is a residue?
Synthesizing enzymes are glycosyltransferases
Do they undergo mutarotation?
Are products stable?

58. Distinctions of disaccharides
The 2 specific sugar monomers involved and their stereoconfigurations (D- or L-)
The carbons involved in the linkage (C-1, C-2, C-4, or C-6)
The order of the two monomer units, if different (example: galactose followed by glucose)
The anomeric configuration of the OH group on carbon 1 of each residue (α or β)

59. Abundant disaccharides
Configuration
Designation
Naming (common vs. systematic)
Reducing vs. non-reducing

62. Raffinose What are oligosaccharide? Example: raffinose
It is found in peas and beans
Homework
What are the names of monosaccharides that make up raffinose?
What is the monosaccharide that is attached to what disaccharide?

63. Oligosaccharides as drugs
Streptomycin and erythromycin (antibiotics)
Doxorubicin (cancer chemotherapy)
Digoxin (cardiovascular disease)

64. Polysaccharides What are polysaccharides?
Homopolysaccharide (homoglycan) vs. heteropolysaccharides

65. Features of polysaccharides
Monosaccharides
Length
Branching

66. Storage polysaccharides
Glycogen
Starch
Dextran

67. Glycogen
Which organisms? Which organs?

68. Structure

69. Starch
Which organisms?
Forms:
amylase (10-20%)
amylopectin (80-90%)

70. Dextran A storage polysaccharide Yeast and bacteria
-(1-6)-D-glucose with branched chains
Branches: 1-2, 1-3, or 1-4

71. Structural polysaccharides

72. Cellulose
Which organism?
Degradation?

73. Structural features? Why?

74. Glycosaminoglycans What are they? Where are they located?
Derivatives of an amino sugar, either glucosamine or galactosamine
At least one of the sugars in the repeating unit has a negatively charged carboxylate or sulfate group

76. Localization and function of GAG
Comments
Hyaluronate
synovial fluid, vitreous humor, ECM of loose connective tissue
the lubricant fluid , shock absorbing
As many as 25,000 disaccharide units
Chondroitin sulfate
cartilage, bone, heart valves
most abundant GAG
Heparan sulfate
basement membranes, components of cell surfaces
contains higher acetylated glucosamine than heparin
Heparin
component of intracellular granules of mast cells lining the arteries of the lungs, liver and skin
A natural anticoagulant
Dermatan sulfate
skin, blood vessels, heart valves
Keratan sulfate
cornea, bone, cartilage aggregated with chondroitin sulfates

77. Bond orientation
Glycosidic bonds in chondroitin 4-sulfate, hyaluronate, dermatan sulfate, and keratan sulfate are alternating  (13) and (14) linkages
Exception is heparin

78. Proteoglycans Lubricants Structural components in connective tissue
Mediate adhesion of cells to the extracellular matrix
Bind factors that stimulate cell proliferation

79. Bacterial cell wall

80. Glycoproteins Soluble proteins as well as membrane proteins Purpose:
Protein folding
Protein targeting
prolonging protein half-life
Cell-cell communication
Signaling

81. Blood typing Three different structures: The difference: A, B, and O
N-acetylgalactosamine (for A)
Galactose (for B)
None (for O)

82. Sialic acid
N-acetylneuraminate, (N-acetylneuraminic acid, also called sialic acid) is derived from the amino sugar, neuraminic acid and is often found as a terminal residue of oligosaccharide chains of glycoproteins giving glycoproteins negative