Lipids Flashcards
What is the structure of glycerol?
H
|
H-C-OH
|
H-C-OH
|
H-C-OH
|
H
What is the structure of a fatty acid?
O
||
HO-C-R
What is a saturated fatty acid?
Only contains single carbon carbon bonds within the R group (hydrocarbon chain) and has no double bonds
What is a mono-unsaturated fatty acid?
Has a single carbon carbon double bond within the R group (hydrocarbon chain)
What is a poly-unsaturated fatty acid?
Has 2 or more carbon carbon double bonds within the R group (hydrocarbon chain)
What bond is formed in the condensation reaction between glycerol and fatty acids?
Ester bond
What products are formed in the condensation reaction between glycerol and fatty acids?
Triglyceride molecule + 3H20
What is a triglyceride?
A molecule consisting of 1 glycerol molecule and 3 fatty acids but is NOT a polymer
What is a phospholipid?
A molecule made from 1 glycerol molecule, 2 fatty acids and a phosphate group with hydrophilic heads (negative phosphate group) and hydrophobic tails (fatty acid chain)
What are the similarities and differences between triglycerides and phospholipids?
Similarities:
- Both contain 1 molecule of glycerol
- Both contain 2 fatty acids
- Both bonded with ester bonds
Differences:
- Phospholipids contain elements C,H,O and P whereas triglycerides contain only C,H and O
- Phospholipids have 2 fatty acids whereas triglycerides have 3
- Phospholipids form a bilayer in water (micelle) whereas triglycerides do not
- Phospholipids are hydrophilic AND hydrophobic whereas triglycerides are ONLY hydrophobic
What is the biochemical test for lipids?
- Add 5cm^3 ethanol to 2cm^3 sample
- Shake the tube thoroughly to dissolve any lipid in the sample
- Add 5cm^3 water and shake gently
- Positive result: cloudy white emulsion
Negative result: stays clear and colourless
