3.5 Lipids Flashcards
Why are lipids non polar?
Electrons in the outer orbitals that form bonds are more evenly distributed than in polar molecules
No positive or negative areas within the molecules
Not soluble in water
Triglyceride
1 glycerol
3 fatty acids
Type of reaction during formation of triglyceride
Condensation & esterification
Glycerol + 3 fatty acids
Triglyceride + 3H2O
Saturated fatty acid
No double bonds between carbon atoms
Mono unsaturated fatty acid
Fatty acid with only one double bond between carbon atoms
Polyunsaturated fatty acid
Two or more double bonds between carbon atoms
Why are unsaturated fatty acids liquid at room temperature?
Presence of double bonds causes kinking, so they cannot pack together very closely
Components of phospholipid
Phosphate group PO43-
Two fatty acid chains
Structure of phospholipid
Tails - non polar/hydrophobic
Head - polar/hydrophilic
How do phospholipids interact with water?
Form a layer on surface of water with phosphate heads in the water and fatty acid tails sticking out
(CALLED SURFACTANTS)
Why are phospholipids important in forming membranes?
They can separate an aqueous environment outside from the aqueous cytosol within cells
Sterol
Complex alcohol molecule
4 Carbon ring structure with OH group at one end
Hydrophobic and hydrophilic region
Cholesterol
Type of sterol
Important in phospholipid membranes - give stability and regulate fluidity
Lipid biological roles
Membrane formation
Hormone production
Electrical insulation for impulse transmission
Waterproofing
