Download 03 - Carbs

Carbohydrates
AP Biology
CH2OH
H
O
H
OH
H
H
OH
HO
H
OH
Carbohydrates
energy
molecules
AP Biology
2006-2007
sugar sugar sugar sugar sugar sugar sugar sugar
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
Photosynthetic Organisms
 Photosynthetic bacteria

Cyanobacteria
 Protists

Spirogyra
 Plants

AP Biology
All are photosynthetic
Monosaccharides
 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
C6H12O6
 Fructose

fruit sugar converted from glucose –
sweetener in honey
 Galactose

AP Biology
Dairy sugar, component of lactose,
necessary for mammals that are
mothers
Polysaccharide diversity
 Molecular structure determines function
in starch
in cellulose
isomers of glucose
 structure determines function…

AP Biology
Glucose
 α – glucose
 β – glucose
 Cannot bond w/ eachother b/c OH + H



does not leave anything behind
Alpha w/ Alpha
Beta/ Beta
We can’t break down cellulose b.c we
don’t have the enzyme
AP Biology
Alpha
Beta
AP Biology
Building sugars
 Dehydration synthesis
monosaccharides
|
glucose
AP Biology
H2O
|
glucose
disaccharide
|
maltose
glycosidic linkage
Building sugars
 Dehydration synthesis
monosaccharides
|
glucose
AP Biology
H2O
|
fructose
disaccharide
|
sucrose
(table sugar)
Dissaccharide C12H22O11
 Maltose –


α-glucose + α- glucose  α-1,4 glycosidic linkage
Found in plant seeds – energy source
 Sucrose

α-glucose + fructose
 Lactose



α-glucose + galactose
Milk sugar
Lactose intolerant – lacking lactase  α-1,4
glycosidic linkage
AP Biology
Polysaccharides
 Polymers of sugars


costs little energy to build
easily reversible = release energy
 Function: (do not copy
below - wait til next slide

energy storage
 starch (plants)
 glycogen (animals)
 in liver & muscles

structure
 cellulose (plants)
 chitin (arthropods & fungi)
AP Biology
energy storage
1. Starch



AP Biology
Amylose (30% of starch) α-1,4 glycosidic
linkage
Amylopectin (70%) α-1,4 and every 30ish
glucose units 1,6 glycosidic linkage
Store in amyloplasts
2. Glycogen (Animal starch)


AP Biology
Humans/animals store in muscle cells and liver
Chains of branching α-glucose (lots of
branches)
Linear vs. branched polysaccharides
slow release
starch
(plant)
energy
storage
glycogen
(animal)
AP Biology
fast
release
What does
branching do?
structure
 3. Cellulose



Primary component of cell walls
Cotton and Paper are purely cellulose
Chain of β glucose - β -1,4 glycosidic linkage
 Humans do not have enzymes to break down
cellulose
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( F FIT
.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.
 4. Chitin


AP Biology
Exoskeletons of arthropods/ fungal cell walls
β -1,4 glycosidic linkage w/ amine chains
EAT
Let’s build
X some
Carbohydrates!
Regents Biology
2006-2007