3.5Lipids Flashcards
What biological molecules make up lipids
Hydrogen
Oxygen
Carbon
What kind of molecules are lipids
Macromolecules
Large complex molecules that aren’t built from monomers
What are lipids main characteristics
Non polar as they have evenly distributed electrons
And have no positive or negative areas and are not soluble
What are types of lipids
Triglycerides
Phospholipids
Sterols
What’s the structure of a triglyceride
1 glycerol molecule with 3 fatty acid chains attached to it (through the hydroxyl groups interacting)
How do they fatty acids attach to the glycerol
Forming ester bonds by the hydroxyl groups in the fatty acid and glycerol
Called esterification
What happens to fatty acid chains with double bonds
What is a saturated fatty acid
They are unsaturated and cause the molecule to kink making it less packed so it becomes liquid form (oily)
Saturated fatty acids have no double bonds, they form the maximum number of bonds with hydrogen atoms
How does a phospholipid differ from a triglyceride
It contains phosphorus and the phosphate group replaces one of the fatty acid chains in a triglyceride
Phosphate has extra elections so are negatively chafed and soluble in water
Why does a phospholipid have hydrophobic and hydrophilic properties
The phosphate ion has extra electrons so its negative making it charged this makes the charged end of the phospholipid hydrophilic and the non polar end of it hydrophobic
What are sterols and what’s there structure
Complex alcohol molecules
They have a 4 carbon ring structure with a hydroxyl group at 1 end
How do they have a hydrophobic / hydrophilic structure
The hydroxyl group is polar so is hydrophilic and the rest of the molecule is hydrophobic
What is cholesterol and what does it do
A type of sterol that forms cell membranes and is postitioned between the phospholipids in the membrane adding stability and regulates the cell membranes fluidity
What are the 4 main roles of lipids
Membrane formation
Hormone production
Electrical insulation
Waterproofing
What are lipids important long term energy store roles
Around the vital organs and under the skin they provide
Thermal insulation
Cushioning
Buoyancy
How do we identify lipids
Using the emulsion test
- Mix with ethanol
- Mix with water and shake
- White emulsion will form as a layer of lipids are present
