Introduction to
Organic Macromolecules
Organic Macromolecules
• Large molecules
• All contain carbon , hydrogen and oxygen
• Some contain other elements
– eg phosphorus or nitrogen
Monomers
the building
blocks of more
complex
molecules,
called
polymers.
Monomers
water
water
Dehydration reaction
Water molecules removed from
monomers bind them to form
polymers
+
+
Monomers
the building blocks of
more complex
molecules, called
polymers.
water
water
Dehydration reaction
Water molecules removed from
monomers bind them to form
polymers
Polymer
consist of repeating
molecular units
which usually are
joined by covalent
bonds.
+
+
Polymer
water
Hydrolysis
The addition of water
molecules breaks the
bonds in a polymer
Monomers
water
Carbohydrates (CHO)
Saccharides = sugars
5C
6C
Monosaccharides = single/simple sugars
Disaccharides = double sugar
Polysaccharide = many/complex sugars
Carbohydrates - Starch:
• is a storage polysaccharide composed entirely of glucose monomers Long chain of glucose molecules 200-500 units
• Used as an energy store in plants.
• Not soluble.
• Forms solid grains inside plant cells (often inside chloroplasts).
• The chains coil up into a basic spiral shape making the molecules compact.
• Hydrogen bonds hold the polysaccharide chain in the compact spiral shape.
Carbohydrates -Glycogen
Carbohydrates- Cellulose
• Most abundant organic molecule.
• 300-10,000 + glucose units
• It is very slow to decompose.
• 20-40% of the plant cell wall.
• Hydrogen bonding between monosaccharide molecules in the chain gives
strength.
• Hydrogen bonding between cellulose molecules cause bundles called
microfibrils to develop. These are held together in fibres.
• A cell wall will have several layers of fibres running in different directions gives great strength almost equal to steel.
• Provides support in plants and stops plant cells bursting.
• Freely permeable to water and solutes.
Lipids ( CHO[P]) :
are built with glycerol and fatty acids
• Structure:
– glycerol (3C alcohol) + fatty acid
 fatty acid =
long HC “tail” with COOH group at “head”
enzyme
dehydration synthesis
Lipids:Building Fats
• Triacylglycerol
– 3 fatty acids linked to glycerol
– ester linkage = between OH & COOH
Lipids:Saturated fats
• All C bonded to H
• No C=C double bonds
– long, straight chain
– most animal fats
– solid at room temp.
• contributes to cardiovascular
disease (atherosclerosis)
= plaque deposits
Lipids:Phospholipids
• Hydrophobic or hydrophilic?
– fatty acid tails = hydrophobic
– PO4 = hydrophilic head
– dual “personality”
interaction with H2O is complex & very
important!
Lipids: Cholesterol
• Important cell component
– animal cell membranes
– precursor of all other steroids
• including vertebrate sex hormones
– high levels in blood may contribute to cardiovascular
disease
Lipids:Cholesterol
Important component of cell membrane
helps keep
cell membranes
fluid & flexible
Amino Acids
• Are the building blocks of proteins.
• Contain a carboxylic acid group and an amino group on the alpha ()
carbon.
• Each contain a different side group (R).
R
│
H2N—C —COOH
AA
Proteins or polypeptides are built with
amino acids (CHON[S])
18
Summary of Protein Structures
Nucleic Acids are built with
nucleotides (NCHOP)
DNA IS MADE OF TWO
STRANDS OF
POLYNUCLEOTIDE
Hydrogen bonds
P
G
C
P
P
C
G
P
P
C
G
P
P
A
T
P
P
T
A
P
P
T
A
P