AP Biology The Chemical Building Blocks 3.2 Carbohydrates
AP Biology
Carbohydrates Carbohydrates are composed of C, H, O
carbo - hydr - ate
CH2O
(CH2O)x C6H12O6
Function: energy energy storage raw materials structural materials
Monomer: sugars
ex: sugars, starches, cellulose
sugar sugar sugar sugar sugar sugar sugarsgar
AP Biology
Sugars Most names for sugars end in -ose Classified by number of carbons
6C = hexose (glucose) 5C = pentose (ribose) 3C = triose (glyceraldehyde)
OH
OH
H
H
HO
CH2OH
HH
H
OH
O
Glucose
H
OH
HO
O H
HHO
H
Ribose
CH2OH
Glyceraldehyde
H
H
H
H
OH
OH
O
C
C
C6 5 3
AP Biology
Sugar structure5C & 6C sugars form rings in solution
Carbons are numberedCarbons are numbered
Where do you find solutions?
In cells!
AP Biology
Numbered carbons
C
CC
C
CC
1'
2'3'
4'
5'
6'
O
energy stored in C-C bondsenergy stored in C-C bonds
AP Biology
Simple & complex sugars Monosaccharides
simple 1 monomer sugars glucose
Disaccharides 2 monomers sucrose
Polysaccharides large polymers starch
OH
OH
H
H
HO
CH2OH
H
H
H
OH
O
Glucose
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Building sugars Dehydration synthesis
glycosidic linkage
|glucose
|glucose
monosaccharides disaccharide
|maltose
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Building sugars Synthesis
|fructose
|glucose
monosaccharides
|sucrose
(table sugar)
disaccharide
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Polysaccharides Polymers of sugars
costs little energy to build easily reversible = release energy
Function: energy storage
starch (plants) glycogen (animals)
structure = building materials cellulose (plants) chitin (arthropods & fungi)
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Linear vs. branched polysaccharides
starch(plant)
glycogen(animal)
energystorage
What doesbranching do?
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Polysaccharide diversity Molecular structure determines function
isomers of glucose structure determines function…
in starch in cellulose
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Digesting starch vs. cellulose
starcheasy todigest
starcheasy todigest
enzyme
enzyme
cellulosehard todigest
cellulosehard todigest
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Cellulose Most abundant organic
compound on Earth herbivores can digest cellulose most carnivores cannot digest cellulose
that’s why they eat meat to get their energy & nutrients
cellulose = roughage
BIG DEAL!Who can live
on this stuff?!
AP Biology
Cowcan digest cellulose well; no need to eat other sugars
Gorillacan’t digest cellulose well; must add another sugar source, like fruit to diet