This document discusses carbohydrates, including their structure, function, classification, and digestion. It notes that carbohydrates are composed of carbon, hydrogen, and oxygen. They function to store energy and act as structural materials. Monosaccharides like glucose are the monomers that make up disaccharides like sucrose and polysaccharides like starch and cellulose. While starch can be easily digested, cellulose is difficult to digest for many organisms. Herbivores have evolved with bacteria in their digestive systems that help break down cellulose.

1. AP Biology
Carbohydrates

2. AP Biology 2006-2007
OH
OH
H
H
HO
CH2OH
H
H
H
OH
O
Carbohydrates
energy
molecules

3. AP Biology
Carbohydrates
 Carbohydrates are composed of C, H, O
carbo - hydr - ate
CH2O
(CH2O)x C6H12O6
 Function:
 energy u energy storage
 raw materials u structural materials
 Monomer: sugars
 ex: sugars, starches, cellulose
sugar sugar sugar sugar sugar sugar sugarsugar
C6H12O6(CH2O)x

4. 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
H
H
H
OH
O
Glucose
H
OH
HO
O H
H
HO
H
Ribose
CH2OH
Glyceraldehyde
H
H
H
H
OH
OH
O
C
C
C
6 5 3

5. AP Biology
Functional groups determine function
carbonyl
ketone
aldehyde
carbonyl

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

7. AP Biology
Numbered carbons
C
CC
C
C
C
1'
2'3'
4'
5'
6'
O
energy stored in C-C bonds

8. 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

9. AP Biology
Building sugars
 Dehydration synthesis
|
glucose
|
glucose
monosaccharides disaccharide
|
maltose
H2O

10. AP Biology
Building sugars
 Dehydration synthesis
|
fructose
|
glucose
monosaccharides
|
sucrose
(table sugar)
disaccharide
Anabolic reactions!
H2O

11. AP Biology
Polysaccharides
 Polymers of sugars
 costs little energy to build
 easily reversible = release energy
 Function:
1. energy storage
 starch (plants)
 glycogen (animals)
 in liver & muscles
2. structure
 cellulose (plants)
 chitin (arthropods & fungi)

12. AP Biology
Linear vs. branched polysaccharides
starch
(plant)
glycogen
(animal)
energy
storage
What does
branching do?
slow release
fast release

13. AP Biology
Polysaccharide diversity
 Molecular structure determines function
 isomers of glucose
 structure determines function…
in starch in cellulose

14. AP Biology
Digesting starch vs. cellulose
starch
easy to
digest enzyme
enzyme
cellulose
hard to
digest

15. 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 = indigestible roughage
But it tastes
like hay!
Who can live
on this stuff?!

16. Regents Biology
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

17. Regents Biology
Helpful bacteria
 How can herbivores digest cellulose so well?
 BACTERIA live in their digestive systems & help digest
cellulose-rich (grass) meals

18. Regents Biology 2006-2007
Let’s build some
Carbohydrates!
EAT
X