1.5 Lipids Flashcards
what are some lipid characteristics?
- contain carbon, hydrogen, oxygen
- proportion of oxygen to carbon and hydrogen is smaller than in carbs
- insoluble in water
- soluble in water e.g. alcohols, acetone
what are the main groups of lipids?
- triglyceride- fats and oils
- phospholipids
what are roles of lipids
phospholipids in cell membrane
=flexibility, transfer of lipid soluble substances
what are roles of lipids?/phospholipids
- source of energy
- waterproofing
- insulation
- protection
how are lipids a good SOURCE OF ENERGY?
- when oxidised provides twice as much energy as the same amount of carbohydrate
- releases valuable water too
how are lipids a good at WATERPROOFING?
- lipids=insoluble in water
- plants+insects: waxy lipid cuticles
- mammals: oily secretion from sebaceous glands in skin
how are lipids a good at INSULATION?
-fats are slow conductors of heat
=retain heat when stored beneath body surface
-act as electrical insulators in myelin sheath around nerve cells
how are lipids a good at PROTECTION?
-fats stored around delicate organs e.g. the kidney
what state are different triglycerides at room temperature? (10-20)
- fats=solid
- oils= liquid
what are triglycerides made from?
3 fatty acids
1 glycerol
how are triglycerides bonded together?
ester bond
condensation reaction
what are the products of the hydrolysis of triglyceride?
3 fatty acids
1 glycerol
what is the word equation for a triglyceride?
glycerol + 3 fatty acids = triglyceride + 3 water
what causes differences in properties of fats and oils?
fatty acids can vary
how many different fatty acid tyoes are there?
over 70
what do all the fatty acids have?
carboxyl (-COOH) group with a hydrocarbon chain attached
what is the carboxyl functional group
(-COOH)
what does saturated mean (fatty acids)?
- no carbon-carbon double bonds
- all carbon atoms liked to maximum number of hydrogen atoms (saturated)
what does monounsaturated mean (fatty acids)?
1 double bond between carbon atoms
what does monounsaturated mean (fatty acids)?
more than 1 double bond between carbon atoms
what effect does the saturation have on fatty acids?
double bonds cause the molecule to bend
=cant pack together closely= liquid at room temp (oil)
