Carbohydrates
AP Biology
CH2OH
H
O
H
OH
H
H
OH
HO
H
OH
Carbohydrates
energy
molecules
AP Biology
2006-2007
Carbohydrates
 Carbohydrates are composed of C, H, O

carbo - hydr - ate
CH2O
(CH22O)
O)xx
C66H12
O
(CH
12 66
Function:
energy
 raw materials
materials

energy storage
 structural

 Monomer: sugars
 ex: sugars, starches, cellulose
AP Biology sugar sugar sugar sugar sugar sugar sugar
sugar
Sugars
 Most names for sugars end in -ose
 Classified by number of carbons
6C = hexose (glucose)
 5C = pentose (ribose)
 3C = triose (glyceraldehyde)

CH2OH
H
O
H
OH
6H
HO
H
AP Biology
OH
Glucose
H
CH2OH
OH
C
O
H
HO
H
5
OH
O
H
HO
H
Ribose
H
H
H
C
OH
C
3OH
H
Glyceraldehyde
Functional groups determine function
carbonyl
aldehyde
carbonyl
ketone
AP Biology
Sugar structure
5C & 6C sugars form rings in solution
Where do
you find solutions
in biology?
In cells!
AP Biology
Carbons are numbered
Numbered carbons
C 6'
5' C
O
4' C
C1'
energy stored in C-C bonds
C3'
AP Biology
C2'
Simple & complex sugars
 Monosaccharides
simple 1 monomer sugars
 glucose

 Disaccharides
2 monomers
 sucrose

 Polysaccharides
large polymers
 starch

AP Biology
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
CH2OH
H
O
H
OH
H
H
OH
HO
Glucose
H
OH
Building sugars
 Dehydration synthesis
monosaccharides
|
glucose
AP Biology
H2O
|
glucose
disaccharide
|
maltose
glycosidic linkage
Building sugars
 Dehydration synthesis
monosaccharides
|
glucose
AP Biology
H2O
|
fructose
Let’s go to the
videotape!
disaccharide
|
sucrose
(table sugar)
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Polysaccharides
 Polymers of sugars
costs little energy to build
 easily reversible = release energy

 Function:

energy storage
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
 starch (plants)
 glycogen (animals)
 in liver & muscles

structure
 cellulose (plants)
 chitin (arthropods & fungi)
AP Biology
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Linear vs. branched polysaccharides
slow release
starch
(plant)
energy
storage
What does
branching do?
glycogen
(animal)
AP Biology
fast
release
Let’s go to the
videotape!
Polysaccharide diversity
 Molecular structure determines function
in starch
in cellulose
isomers of glucose
 structure determines function…

AP Biology
Digesting starch vs. cellulose
starch
easy to
digest
enzyme
cellulose
hard to
digest
enzyme
AP Biology
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
AP Biology
But it tastes
like hay!
Who can live
on this stuff?!
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
Regents Biology
Helpful bacteria
 How can herbivores digest cellulose so well?

BACTERIA live in their digestive systems & help digest
cellulose-rich (grass) meals
a dna ™emiTkciuQ
rosserpmoced )desserpmocnU( FFIT
.erutcip siht ees ot dedeen era
Caprophage
Ruminants
Regents Biology
Tell Ime
about
eat
the rabbits,
WHAT!
again,
George!
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
EAT
Let’s build
X some
Carbohydrates!
Regents Biology
2006-2007