AP Biology: Chapter 5
Structure and Function of
Macromolecules:
CARBOHYDRATES
Polymer Principles
• Most macromolecules are polymers
• Polymer-large molecule consisting of
many identical or similar subunits
connected together.
• Monomer- subunit or building block of
a polymer
• Macromolecule- large organic
polymer
Figure 5.1 Building models to study the structure and
function of macromolecules
Classes of Macromolecule in
living organisms
• Carbohydrates- used as fuel and
building material
• Lipids-energy storage
• Proteins-structure, movement,
enzymes
• Nucleic acids-store and transmit
hereditary information.
Polymerization
Reactions
• Formation of macromolecules
from smaller building block
molecules represents another
level in the hierarchy of
biological organization.
• Most polymerization reactions
are condensation (dehydration)
reactions.
Condensation Reactions
• Monomers are covalently linked with
the removal of a water molecule at
each linkage
• One monomer loses a hydroxyl
(-OH), and the other monomer loses a
hydrogen (-H).
• Process requires energy, and the
presence of a biological catalyst
Hydrolysis Reaction
• Reaction that breaks covalent bonds
between monomers by the addition
of water molecules.
• A H+ from the water bonds to one
monomer, and the OH- bonds to the
adjacent monomer.
• Example: Hydrolytic reactions break
down food molecules into monomers
that can be absorbed in the blood.
Carbohydrates
• Sugars and starches used for fuel
and building material
• Monosaccharides- simple sugar
building blocks (monomers)
• Polymers are chains of monomers
formed by condensation reactions
• Carbohydrates are classified by the
number of simple sugars in the
compound
Monosaccharides
• Simple sugar in which C, H, and O
are in a ration of 1:2:1 (CH2O)
• Can be produced by photosynthetic
organisms from CO2, H2O, and
sunlight (glucose)
• Cellular respiration releases energy
in chemical bonds.
• Monomers for disaccharides and
polysaccharides.
Characteristics of Sugars
• --OH group attached to each carbon
except one, which has a carbonyl
group (C=O)
• Size of the carbon skeleton varies
from 3-7 carbons
• Spatial arrangement may vary, such
as with enantiomers
• In aqueous solution, most
monosaccharides form rings.
Disaccharides
• Double sugar formed from two
monosaccharides joined by a
glycosidic linkage.
• Examples:
Maltose = glucose + glucose (beer)
Lactose = glucose + galactose (milk)
Sucrose = glucose + fructose (table
sugar)
Polysaccharides
• Polymers of sugars, have
storage and structural roles
• Formed by linking monomers by
condensation reactions
• Important biological functions:
energy storage (starch and
glycogen) and structural support
(cellulose and chitin)
Storage polysaccharides
• Starch and glycogen can be
hydrolyzed into sugars as
needed.
• Starch is stored in plants in
plastids. Most animals have
enzymes to digest starch.
• Glycogen is stored in the
muscles and liver of animals.
Structural polysaccharides
• Cellulose: major component of
plant cell walls, cannot be
digested by most organisms
because of B 1-4 linkage
• Chitin: polymer of amino sugar,
forms exoskeletons of
arthropods, cell walls of fungi