Post on 05-Jan-2016
Macromolecules
4 major classes of macromolecules:carbohydrateslipidsproteinsnucleic acids
– monomers • building blocks• repeated small units
– polymers • Molecules consisting of 2 or more
monomers
Dehydration synthesis / CondensationDehydration synthesis / Condensation
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H2O
HO
HO H
H HHO
Polymer Formation (synthesis)
-joins monomers by “taking” H2O out• one monomer donates OH–
• other monomer donates H+ • together these form H2O• requires energy & enzymes
enzymeDehydration synthesis / CondensationDehydration synthesis / Condensation
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H2O
HO H
HO H HO H
Polymer Breakdown (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
enzymeHydrolysisHydrolysis
Carbohydrates -Composed of C, H, O carbo-hydrate CH2O
C6H12O6
Most names for sugars end in -ose Classified by number of carbons
6C = hexose (glucose) 5C = pentose (ribose) 3C = triose (glyceraldehyde)
*5C & 6C sugars form rings in solution
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Types of Carbohydrates
• Monosaccharides– 1 simple sugar (monomers)– glucose, galactose, fructose
• Disaccharides– 2 monosaccharides – sucrose, maltose, lactose
• Polysaccharides – 3 or more monosaccharides
(polymers)– starch, cellulose, chitin, glycogen
OH
OH
H
H
HO
CH2OH
HH
H
OH
O
Glucose
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glucose glucose maltose 1,4 glycosidic linkage
*Position of linkage determines function
glucose fructose sucrose 1,2 glycosidic linkage
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Polysaccharides Polymers of sugars Function:
energy storage starch (plants) glycogen (animals)
structure = building materials cellulose (plants) chitin (arthropods & fungi)
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Unbranched vs Branched
starch(plant)
glycogen(animal)
p62 Fig 5.6
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Structural PolysaccharidesCellulose makes up plant cell walls and differs from starch by glycosidic linkagesp63 Fig 5.7
starch cellulose
*isomers of glucose
alpha = below plane....all beta = above plane....every other
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Digesting starch vs. cellulose
cellulosehard todigest
cellulosehard todigest
starcheasy todigest
starcheasy todigest
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Structure
Cellulose -straight -chains...H-bonds
Starch-helical
http://bcs.whfreeman.com/thelifewire/content/chp03/0302002.html