energy storage = large ratio of energy storing carbon - hydrogen bonds compared to number of carbon atoms
Act as metabolic water source = high ratio of hydrogen to oxygen atoms, can release water if oxidised
Don’t affect water potential and osmosis, large and hydrophobic so insoluble in water
Lipids have low mass= store a lot without increasing mass and preventing movement
Features of unsaturated fatty acids
contain C=Cdouble bonds- kinked molecules have fewer contact points
Lower melting point = liquid at room temperature
Found in plant oils
Functions of membranes in cells
provide internal transport system= selectively permeable to regulate passage of molecules into and out of organelles
Provide reaction surface = isolate organelles from cytoplasm for specific metabolic reactions
How are triglycerides formed
Condensation of one molecule of glycerol and three molecules of fatty acids
Two groups of lipids
triglycerides
Phospholipids
What bond forms during the condensation reaction between a glycerol and a fatty acid
Ester bond
Test for lipids
dissolve solid samples in ethanol
Add equal volume of water and shake
Positive result= milky white emulsion forms
Phospholipids are made up of two fatty acids and a phosphate group attached to a glycerol backbone.
Phospholipid bilayers form the membranes that surround cells and organelles.
Cholesterol is an important component of cell membranes as it helps to maintain their fluidity at different temperatures.
Function of phospholipids
Contain a hydrophobic tail and hydrophylic phosphate head - form a bilayer within cell Surface membranes in aqueous environments
Hydrophilic head helps hold at the surface of cell surface membrane
Phospholipid structure allows them to make glycolipids by combining with carbohydrates within the cell surface membrane- glycolipids important in cell recognition