Lipids Flashcards
What are the two types of lipid and where are they found?
Wax - alcohol ester bonded by a condensation reaction to one fatty acid.
Eg: waxy cuticle on leaves, waxy cuticle on exoskeletons.
Triglycerides - glycerol ester bonded by condensation reaction to three fatty acid
Eg: food like butter, oil and other edible fats
What are lipids?
Macromolecules
What are the main properties of lipids?
- Non polar
- Insoluble in water
- Soluble in organic/non polar solvents (acetone & ether)
- Energy dense (more energy per gram than glucose)
What is the difference between saturated and unsaturated fatty acids?
Saturated - no double carbon bonds in hydrocarbon chain.
Unsaturated - one or more double carbon bond in hydrocarbon chain
How does a triglyceride form?
- A condensation reaction between hydroxyl group of glycerol and the OH of the carboxyl group of the fatty acids
- Ester bond forms
What happens if one or more of the fatty acids are unsaturated?
Unsaturated triglyceride forms which have a lower melting point
What is a phospholipid?
Main component in cell membranes- forms the phospholipid bilayer
What is the structure of a phospholipid bilayer?
- Polar hydrophilic phosphate head faces outwards (towards water)
- Non-polar hydrophobic fatty acid tails face in (away from water)
What is the structure of a phospholipid?
- ‘Head’ contains a phosphate group
- Two ‘tails’ of fatty acids
- Joined by a glycerol molecule
What are the uses/roles of lipids?
Energy store - hibernation, germination
Buoyancy - Blubber
Insulation - Thermal & electrical
Protection - Shock absorber
Water resistance - Ducks & leaves
Reducing water loss - camels & kangaroo mice
Structural role - cell membranes
What is the structure of fatty acids?
A carboxyl group (COOH) with a non-polar hydrocarbon chain/tail
What is the general formula of fatty acids?
COOH-R
What is the general formula of saturated fatty acids?
COOH-CH3(CH2)n
What are the properties of fats?
- Solid of room temp
- Most are saturated
- Found in animals
What are the properties of oils?
- Liquid at room temp
- Contain unsaturated fatty acids
- Found in plant