Lipids Flashcards
Lipids:
A diverse group of compounds that are insoluble in water but are soluble in organic solvents such as ethanol
They contain Hydrogen (high proportion), Oxygen (low proportion), and carbon
> Triglycerides (fats)
> Waxes
> Steroids
> Cholesterol
Lipids: Role
(Adipose tissues)
> Energy source (38kJ/g)
> Heat insulation: adipose tissue reduces heat loss in mammals
> Protection: adipose tissue surrounds and cushions delicate organs (kidneys) against impacts
Forming triglycerides:
Glycerol + 3 fatty acids
(condensation reaction)
> Linked by 3 ester bonds
> Producing 3 water molecules
Saturated bonds:
No double bonds between carbon atoms
Monounsaturated bonds:
One double bond between carbon atoms
Polyunsaturated bonds:
More than one double bond between carbon atoms
Double bonds make the molecule bend so they cannot pack together as closely - they are liquid at room temperature (oils)
Phospholipid: Structure
Phosphate + 2 fatty acids
Phosphate head:
> Charged
> Hydrophilic
Tail:
> Non - polar, long chained hydrocarbons
> Hydrophobic
Emulsion Test: (safety)
> Ethanol is highly flammable
(do not use near naked flames, touch, inhale, or swallow)
Do not use nuts if allergic
Emulsion Test: (equipment)
> Scalpel and tile / pestle and mortar
Labelling equipment
Spatulla
Test tubes, bung, rack
Distilled water (wash bottle)
Pasteur pipettes
Paper towels
Large plastic waste beaker
250cm3 beaker of distilled water
Ethanol / IMS
Olive / plant oil in dropper bottle
Dry food material (biscuit, potato)
Emulsion Test: (Method)
1) Label test tubes for foods
2) Chop/grind solid food
3) Add food to labelled test tube
4) Add two drops of oil
5) Add 3cm3 of ethanol
6) Put clean bung in
7) Shake 10 times
8) Wait for ethanol above food to clear
9) Use wash bottle to add 3cm depth of distilled water
10) Observe and note any changes in the test tube contents in a table
