Chapter 5.
Macromolecules
AP Biology
2005-2006
Macromolecules
 Smaller organic molecules join together
to form larger molecules

macromolecules
 4 major classes of macromolecules:
carbohydrates
 lipids
 proteins
 nucleic acids

AP Biology
2005-2006
Polymers
 Long molecules built by linking chain
of repeating smaller units
polymers
 monomers = repeated small units
 covalent bonds

AP Biology
2005-2006
How to build a polymer
 Condensation reaction
dehydration synthesis
 joins monomers by “taking” H2O out

 1 monomer provides OH
 the other monomer provides H
 together these
form H2O

AP Biology
requires energy
& enzymes
2005-2006
How to break down a polymer
 Hydrolysis

use H2O to break apart monomers
 reverse of condensation reaction
 H2O is split into H and OH
 H & OH group attach where the covalent
bond used to be

AP Biology
ex: digestion is
hydrolysis
2005-2006
Carbohydrates
AP Biology
2005-2006
So what’s all this talk
about carbs?
Atkin’s Diet
South Beach Diet
AP Biology
2005-2006
Carbohydrates
 Carbohydrates are composed of C, H,
O carbo - hydr - ate
CH2O
(CH2O)x
C6H12O6
 Function:
energy
 raw materials

energy storage
◆ structural materials
◆
 Monomer: sugars
 ex: sugars & starches
AP Biology
2005-2006
Sugars
 Most names for sugars end in -ose
 Classified by number of carbons
6C = hexose (glucose)
 5C = pentose (fructose, ribose)
 3C = triose (glyceraldehyde)

AP Biology
2005-2006
What functional groups?
carbonyl
aldehyde
ketone
hydroxyl
AP Biology
2005-2006
Sugar structure
 5C & 6C sugars form rings in aqueous solutions

in cells!
Carbons are numbered
AP Biology
2005-2006
Numbered carbons
C 6'
5' C
O
C
4'
C1'
C3'
AP Biology
C2'
2005-2006
Simple & complex sugars
 Monosaccharides
simple 1 monomer sugars
 glucose

 Disaccharides
2 monomers
 sucrose

 Polysaccharides
large polymers
 starch

AP Biology
2005-2006
Building sugars
 Dehydration synthesis
monosaccharides
|
glucose
|
glucose
disaccharide
|
maltose
glycosidic linkage
AP Biology
2005-2006
Building sugars
 Dehydration synthesis
monosaccharides
|
glucose
|
fructose
structural isomers
disaccharide
|
sucrose
glycosidic linkage
“Let’s go to the video tape!”
AP Biology
(play movie here)
2005-2006
Polysaccharides
 Polymers of sugars
costs little energy to build
 easily reversible = release energy

 Function:

energy storage
 starch (plants)
 glycogen (animals)

building materials = structure
 cellulose (plants)
 chitin (arthropods & fungi)
AP Biology
2005-2006
Branched vs linear polysaccharides
AP Biology
2005-2006
Polysaccharide diversity
 Molecular structure determines function
isomers of glucose
 How does structure influence function…

AP Biology
2005-2006
Digesting starch vs. cellulose
AP Biology
2005-2006
Cellulose
 Most abundant organic compound
on Earth
AP Biology
2005-2006
Glycemic index
 Which food will get into your
blood more quickly?





AP Biology
apple
rice cakes
corn flakes
bagel
peanut M&M
2005-2006
Glycemic index
 Ranking of carbohydrates based on their

immediate effect on blood glucose (blood
sugar) levels
Carbohydrate foods that breakdown quickly
during digestion have the highest glycemic
indices. Their blood sugar response is fast &
high.
AP Biology
2005-2006
Glycemic index
 Which food will get into your
blood more quickly?





AP Biology
apple
rice cakes
corn flakes
bagel
peanut M&M
36
82
84
72
33
2005-2006
Let’s build some
Carbohydrates!
AP Biology
2005-2006