Biological molecules - lipids Flashcards
What is the structure of a triglyceride
it has 3 fatty acids and 1 glycerol
What is the structure of the fatty acids
They have long tails made of hydrocarbons
The tails are hydrophobic-repel water which makes lipids insoluble in water
How is a triglyceride formed
When an ester bond if formed a molecule of water is released and the happens 3 times to form the triglyceride as 3 fatty acids must join to the glycerol
What is a saturated fatty acid
They have no double bonds
What is an unsaturated fatty acids
They have at least one double bond
What are phospholipids
They have 2 fatty acids, 1 glycerol and 1 phosphate group
They are hydrophilic and attract water
What are the structural elements of a fatty acid
Long hydrocarbon tails
Insoluble
How does having a long tail help
triglycerides
The tails have a lot of energy as lots of energy is released when they are broken down
How does being insoluble affect triglycerides
They don’t affect the water potential of the cell so don’t allow water in (which would make them swell)
What are the structural elements of phosphlipids
They have HYDROPHILLIC heads and HYDROPHOBIC tails
The centre of the bilayer is hydrophobic
How does the centre of the bilayer being hydrophobic help phospholipids
Water soluble molecules cant easily pass through it
What is the emulsion test for lipids
Add ethanol to the test tube sample and shake for a minute so it dissolves and then pour the solution into water - a positive test is a milky emulsion
