Chapter 5- The Structure and Function of Macromolecules Carbohydrates

1. Chapter 5- The Structure and Function of MacromoleculesCarbohydrates AP BIOLOGY

2. Macromolecules • Carbohydrates • Proteins • Lipids • Nucleic Acids

3. Carbohydrates

4. Polymer Vs. Monomer • Polymer: A large molecule made up of identical or similar building blocks • Ex. Polysaccaride • Starches • Monomer: the building block that is used to make polymers • Glucose

5. Carbohydrates • Carbohydrates are composed of C, H, O • Most names for sugars end in –ose • CH2O (Empirical Formula) (CH2O)C6H12O6 • Contains a Carbonyl (C=O) & many Hydroxyl (OH) • Function: Energy & Storage • ex: sugars, starches, cellulose, chitin (CH2O)x C6H12O6

6. sugar sugar sugar sugar sugar sugar sugar sugar Monosaccharides • Simple 1 monomer sugars • Ex’s: • Glucose • Frucotose • Galactose

7. Biological function of monosaccharides • ENERGY!!!! • Key parts of other molecules (e.g. nucleic acids, ATP) • Monomers for Disaccharides & Polysaccharides. • They form polymers in dehydration reactions.

8. Classifying Monosaccharides • Monosaccharides are uniquely identified based on: • The location of the carbonyl carbon in the straight chain form • The number of carbons present • The spatial arrangement of carbons

9. Sugar structure 5C & 6C sugars form rings in solution Where do you find solutionsin biology? In cells!

10. Identifying monosaccharides • The arrangement of the –OH group on the #1 carbon does not matter when naming sugars. • The location of the other groups on the 2,3,4, and 5 carbons does matter. alpha-glucose beta-glucose

11. Carbons are numbered C 6' C O 5' C C 4' 1' energy stored in C-C bonds C C 3' 2'

12. H O C CH2OH CH2OH C OH O H H O H H H OH H OH H C H HO OH HO HO H H H OH OH H Glyceraldehyde Glucose Ribose Carbon Skeleton • 3-7 Carbons long • Classified by number of carbons • 6C = hexose (glucose) • 5C = pentose (ribose) • 3C = triose (glyceraldehyde) 6 5 3

13. Functional groups determine function Aldehyde Carbonyl at end Ketone Carbonyl in middle

14. Forming Disaccharides glucose+ glucose= Disaccharide monomermonomerPolymer

15. Disaccharides • 2 monomers • Held by glycosidic bonds • Ex’s • Sucrose • Lactose • Maltose

16. H2O Building sugars • Dehydration synthesis monosaccharides disaccharide sucrose (table sugar) | glucose | fructose

17. H2O Building sugars monosaccharides disaccharide glycosidic linkage | glucose | glucose | maltose

18. Lactose

19. Glucose and Fructose Glucose

20. Polysaccharides • Polymers of sugars • costs little energy to build • Function: • energy storage • starch (plants) • glycogen (animals) • in liver & muscles • structure • cellulose (plants) • chitin (arthropods & fungi)

21. Polysaccharides • Polymers of sugars joined by glycosidic linkages. • Serve two main functions • Storage- glycosidic linkages are hydrolyzed to obtain monosaccharides as energy is needed. • Structural- make up the materials that are used to protect the organism.

22. GlycosidicBonds • Chemical linkage between the monosaccharide units of disaccharides, and polysaccharides, which is formed by the removal of a molecule of water • Condensation reaction • Bond forms between the carbon-1 on one sugar and the carbon-4 on the other.

23. Α & β Glycosidic Bonds • An α-glycosidic bond- formed when the –OH group on carbon-1 is below the plane of the glucose ring • A β-glycosidic bond is formed when it is above the plane. • Ex. Cellulose- formed of glucose molecules linked by 1-4 β-glycosidic bonds (Above plane) • Ex. Starch- composed of 1-4 α-glycosidic bonds (Below plane ) in cellulose in starch

24. Polysaccharides- 100’s to 1000’s of monosaccharides

25. Structural Polysaccharides • Key in forming the structure of an organism. • Most common structural polysaccharide is cellulose. • Makes up cell walls in plants • Used to make paper • Chitin • Polymer of glucose • Forms via 1-4 glycosidic linkage.

26. Cellulose • Most abundant organic compound on Earth • herbivores have evolved a mechanism to digest cellulose • most carnivores have not • cellulose = undigestible roughage But it tasteslike hay!Who can liveon this stuff?!

27. Cow can digest cellulose well; no need to eat other sugars Gorilla can’t digest cellulose well; must add another sugar source, like fruit to diet

28. Helpful bacteria • How can herbivores digest cellulose so well? • BACTERIA live in their digestive systems & help digest cellulose-rich (grass) meals Rumen-Upper part of stomach

29. enzyme enzyme Digesting starch vs. cellulose starcheasy todigest cellulosehard todigest

30. Plant Storage Polysaccharides • Starch is the main storage polysaccharide- Found in two forms. • Amylose- main storage polysaccharide found in plants. • 1-4 glycosidic linkage found in glucose. • Amylopectin- also in plants. • Like starch with branching. • Branch occurs with a 1-6 glycosidic link.

31. Storage Polysaccharide in Animals • Glycogen is the main storage polysaccharide in animals. • It is even more highly branched than amylopectin. • Stored primarily in muscle and liver cells and is used when glucose stores are low.

32. Polysaccharide diversity • Molecular structure determines function in starch in cellulose • isomers of glucose • structure determines function…

33. Linear vs. branched polysaccharides slow release starch (plant) energystorage glycogen (animal) fast release

34. Mitochondria Chloroplast Starch Glycogen granules Fig. 5-6 0.5 µm 1 µm Glycogen Amylose Amylopectin Starch Unbranched Glycogen Branched

35. Difference between starch and cellulose • Starch production involves 1-4 glycosidic linkage of a-glucose monomers. • Helical shape • Cellulose production involves 1-4 glycosidic linkage of b-glucose monomers • Never branched , straight • a- Glycogen • b- Cellulose • Does this matter?

36. Fig. 5-7a  Glucose  Glucose (a)  and  glucose ring structures

37. Fig. 5-7bc (b) Starch: 1–4 linkage of  glucose monomers (c) Cellulose: 1–4 linkage of  glucose monomers

38. Chitin • Chitin is the structuralpolysaccharide in arthropods • Ex. insects, spiders, crustaceans, and fungi. • Similar to cellulose, but it has a slightly different monomer that is a derivative of glucose

39. Fig. 5-10 (a) (c) (b) Chitin forms the exoskeleton of arthropods. The structure of the chitin monomer. Chitin is used to make a strong and flexible surgical thread.

40. YES, It matters! • Cellulose has a much different structure than starch. • In storage polysaccharides, the polymer hydrogen bonds mainly with itself to form helices (spirals) • Ex. Glycogen • In structural polysaccharides, the polymer hydrogen bonds with other polymer strands to form a strands that form thread like structures • Ex. Chitin & Cellulose

41. Starch vs. Cellulose Helix Sheet

42. IT REALLY MATTERS • Animals lack the enzymes (cellular machinery) to break down cellulose. • Only a few bacteria and fungi can break down cellulose.