Download Macromolecules

Macromolecules
Macromolecules are polymers of similar units (monomers) linked
together.
There are four classes of macromolecules in cells:
1.
2.
3.
4.
CARBOHYDRATES
LIPIDS
PROTEINS
NUCLEIC ACIDS
(polymers of sugars)
(polymers of fatty acids)
(polymers of amino acids)
(polymers of nucleotides)
1. CARBOHYDRATES
Function: Major energy source
Structure: C(H2O)
(ratio 1C:1H2O )
1) Simple Carbohydrates
Monomers can have 5 (pentose) or 6 (hexose) carbons.
A) Monosaccharides
i) glucose
ii) fructose
iii) galactose
B) Disaccharides (double sugars)
i) Maltose (glucose + glucose)
ii) Sucrose (glucose + fructose)
iii) Lactose (galactose + glucose)
2) Complex Carbohydrates (Polysaccharides)
Formed from many mono/disaccharides joining together.
A) Storage Polysaccharides
Starch (plants)
• Insoluble; can exist as amylose (unbranched) or amylopectin
(branched) polymer. e.g.
Glycogen (animals)
• Insoluble; branched polymer, even more branches than amylopectin.
e.g.
B) Structural Polysaccharides
Cellulose
• Linear, unbranched polysaccharide with glucose in beta-1,4 linkages
• Forms fibrils which reinforce plant cell walls
• Cannot be digested by animals because they lack an enzyme to break
beta-1,4 linkages. e.g.
Chitin
• a polymer of an amino sugar
• tough, leathery polymer which makes up insect and crustacean
exoskeletons
• if combined with calcium, it can become hard
• also found in fungal cell walls instead of cellulose