Lipids Flashcards
Identify three uses of lipids in animals
3 marks
Energy store Energy source Buoyancy Insulation Protection
what three elements do they contain
3 marks
Oxygen , carbon and hydrogen
Which lipids are most important to animals?
Triglyceride, steroid, phospholipid
Discuss the structure of the molecule ( triglyceride ) including hydrophobic and hydrophilic
4 marks
A triglyceride has a glycerol molecule that is bonded to three fatty acids using a condensation reaction to form an ester bond. The molecule is hydrophilic and the glycerole head (interacts with water) and hydrophobic from the hydrocarbon chains on the fatty acid tails this repels water.
what is the difference between saturated and unsaturated lipids
The saturated lipid has a no double bond whereas the unsaturated lipid has double bond
where is unsaturated fats mainly found
olive oil , nuts , oily fish
How does the presence of a double bond affect the boiling point of a unsaturated molecule
the boiling point is reduced due the double bond being weaker.
How many condensation reaction are needed to form a triglyceride
3
What is the structure of a phospholipid
A phosphate head that is hydrophilic 2 fatty acid chains that are hydrophobic due to them being non polar. All joined to a glycerol
How are phospholipds used in the body
They are used for the phospholipid bilayer of the membrane for cells.
How do the phospholipids react to water
They are amphipathic due to the opposite ends of polarity and therefore they normally form the shape of a micelle having all hydrophilic interactions facing the outside and all hydrophobic facing in.
What is the structure of the phospholipid bilayer
2 layers of phospholipids that are oppositely facing. The membrane moves freely but it does not allow the hydrophobic tails to interact with water.
What is the purpose of cholesterol
Cholesterol are used to produce steroid hormones and to regulate the fluidity of the bilayer
