Download Carbohydrates

MACROMOLECULES
Four Types of Macromolecules
1.
2.
3.
4.
Carbohydrates
Lipids
Proteins
Nucleic Acids
Carbohydrates
 commonly
found in foods: sugars and
starches

these compounds always contain carbon,
hydrogen and oxygen in a 1:2:1 ratio or CH2O

provide short or longer term energy storage for
living organisms

provide structural support
Types of Carbohydrates
1.
2.
3.
Monosaccharides
Disaccharides
Polysaccharides
1. Monosaccharides
 simple
sugar containing 3 to 7 carbons
 examples: glucose, fructose, galactose
(isomers – same chemical formula
C6H12O6 but different 3D structure
 provides instant
energy
ring
 Monosaccharides become ring shaped
when in the presence of water.
2. Disaccharides
 made
up of two monosaccharides
 common examples:
glucose + glucose = maltose
glucose + galactose = lactose
glucose + fructose = sucrose
Disaccharides… cont’d
formed
by a condensation reaction
(dehydration synthesis)
 for maltose – a link forms between
carbon 1 on one glucose and carbon 4
of the other.
this creates a 1-4 glycosidic linkage
water is released
Sucrose contains a 1-2 glycosidic link.
Making & Breaking Carbohydrates
monosaccharide
+
monosaccharide
disaccharide (di = two)
Condensation (dehydration) synthesis
Hydrolysis
Two important
biochemical reactions
Carbohydrates – Complex (Polysaccharides)
 Main Function: quick and short-term energy storage
 Contain many units of glucose in long chains
 Examples: Starch, glycogen, cellulose
Starch = energy storage in
plants
Starch Granules (purple) in Potato Cells
Starch

made up of amylose (straight chain glucose
polymer) and amylopectin (branched
glucose polymer).
 large insoluble molecule found in
specialized storage plant structures (tubers
in potatoes, fruit of corn, wheat, rice…)
 how plant stores extra glucose made during
photosynthesis
Carbohydrates – Complex (Polysaccharides)
Glycogen (polymer)
Glucose (monomer)
Glycogen = energy storage
in animals
muscle
liver
Glycogen (red) in Hepatocytes (liver cells)
Carbohydrates – Complex (Polysaccharides)
Cellulose fibers
Cellulose = polysaccharide
found in plant
cell walls
Macrofibril
Microfibril
Chains of
cellulose
Cellulose

straight chain glucose
polymer
 chains packed into
bundles called
microfibrils
 provide support in cell
wall
 main structural
component of plants
Makes starch
(can digest)
Makes cellulose
(can’t digest)
Chitin
 exoskeleton
of insects and crustaceans
(provides protection)
 straight chain glucose polymer with
nitrogen group at carbon 2