CH. 5 Macromolecules

1. CH. 5 Macromolecules Building Blocksof Life

2. Macromolecules • Smaller organic molecules join together to form larger molecules • macromolecules • 4 major classes of macromolecules: • carbohydrates • lipids • proteins • nucleic acids

3. H2O HO H HO H HO H Polymers • Long molecules built by linking repeating building blocks in a chain • monomers • building blocks • repeated small units • covalent bonds Dehydration synthesis

4. H2O HO H HO H enzyme HO H How to build a polymer You gotta be open to“bonding! • Synthesis • joins monomers by “taking” H2O out • one monomer donates OH– • other monomer donates H+ • together these form H2O • requires energy & enzymes Dehydration synthesis Condensationreaction

5. H2O HO H enzyme H HO H HO How to break down a polymer Breaking upis hard to do! • Digestion • use H2O to breakdown polymers • reverse of dehydration synthesis • cleave off one monomer at a time • H2O is split into H+ and OH– • H+ & OH– attach to ends • requires enzymes • releases energy Hydrolysis Digestion

6. sugar sugar sugar sugar sugar sugar sugar sugar Carbohydrates • Carbohydrates are composed of C, H, O carbo - hydr - ate CH2O (CH2O)x C6H12O6 • Function: • energy uenergy storage • raw materialsustructural materials • Monomer: sugars • ex: sugars, starches, cellulose (CH2O)x C6H12O6

7. 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 Sugars • Most names for sugars end in -ose • Classified by number of carbons • 6C = hexose (glucose) • 5C = pentose (ribose) • 3C = triose (glyceraldehyde) 6 5 3

8. Functional groups determine function carbonyl aldehyde carbonyl ketone

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

10. Numbered carbons C 6' C O 5' C C 4' 1' energy stored in C-C bonds C C 3' 2'

11. CH2OH O H H H OH H OH HO H OH Glucose Simple & complex sugars • Monosaccharides • simple 1 monomer sugars • glucose • Disaccharides • 2 monomers • sucrose • Polysaccharides • large polymers • starch

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

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

14. Linear vs. branched polysaccharides slow release starch (plant) What doesbranching do? energystorage glycogen (animal) Let’s go to the videotape! fast release

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

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

17. Cellulose • Most abundant organic compound on Earth • herbivores have evolved a mechanism to digest cellulose • most carnivores have not • that’s why they eat meat to get their energy & nutrients • cellulose = undigestible roughage But it tasteslike hay!Who can liveon this stuff?!

18. 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

19. Helpful bacteria • How can herbivores digest cellulose so well? • BACTERIA live in their digestive systems & help digest cellulose-rich (grass) meals Tell me aboutthe rabbits,again, George! I eatWHAT! Ruminants

20. long term energy storage concentrated energy Lipids

21. Lipids • Lipids are composed of C, H, O • long hydrocarbon chains (H-C) • “Family groups” • fats • phospholipids • steroids • Do not form polymers • big molecules made of smaller subunits • not a continuing chain

22. enzyme H2O Fats • Structure: • glycerol (3C alcohol) +fatty acid • fatty acid = long HC “tail” with carboxyl (COOH) group “head” dehydration synthesis

23. Building Fats • Triacylglycerol • 3 fatty acids linked to glycerol • ester linkage = between OH & COOH hydroxyl carboxyl

24. enzyme enzyme enzyme H2O H2O H2O H2O Dehydration synthesis dehydration synthesis

25. Why do humanslike fatty foods? Fats store energy • Long HC chain • polar or non-polar? • hydrophilic or hydrophobic? • Function: • energy storage • concentrated • all H-C! • 2x carbohydrates • cushion organs • insulates body • think whale blubber!

26. Saturated fats • All C bonded to H • No C=C double bonds • long, straight chain • most animal fats • solid at room temp. • contributes to cardiovascular disease (atherosclerosis) = plaque deposits

27. Unsaturated fats • C=C double bonds in the fatty acids • plant & fish fats • vegetable oils • liquid at room temperature • the kinks made by doublebonded C prevent the molecules from packing tightly together mono-unsaturated? poly-unsaturated?

28. Phospholipids • Structure: • glycerol + 2 fatty acids + PO4 • PO4 = negatively charged

29. Phospholipids • Hydrophobic or hydrophilic? • fatty acid tails = • PO4 head = • split “personality” hydrophobic hydrophillic “attracted to water” Come here,No, go away! Come here,No, go away! interaction with H2O is complex & very important! “repelled by water”

30. Phospholipids in water • Hydrophilic heads “attracted” to H2O • Hydrophobic tails “hide” from H2O • can self-assemble into “bubbles” • bubble = “micelle” • can also form a phospholipid bilayer • early evolutionary stage of cell? water bilayer water

31. Why is this important? • Phospholipids create a barrier in water • define outside vs. inside • they make cell membranes! Tell themabout soap!

32. Steroids • Structure: • 4 fused C rings + ?? • different steroids created by attachingdifferentfunctional groups to rings • different structure creates different function • examples:cholesterol, sex hormones cholesterol

33. Cholesterol • Important cell component • animal cell membranes • precursor of all other steroids • including vertebrate sex hormones • high levels in blood may contribute to cardiovascular disease

34. Cholesterol helps keep cell membranes fluid & flexible Important component of cell membrane

35. From Cholesterol  Sex Hormones • What a big difference a few atoms can make!