lipid Structure Flashcards
what elements do lipids contain?
Carbon, hydrogen, oxygen
give two examples of lipids
fats and oils
what state are fats at room temperature?
solid
what state are oils at room temperature?
liquid
Describe the properties of lipids
- large
- varied group of non-polar molecules
- insoluble in water
- dissolve easily in organic substances
what are triglycerides mainly made up of ?
- 3 fatty acids
- 1 glycerol molecule
what is meant by the term saturated ?
no double bonds between the carbon atoms
what is meant by the term unsaturated ?
one or more double bonds between carbon atoms
what is glycerol made up off?
-3 hydroxyl groups
each of which can combine with a fatty acid to form a triglyceride
what type of reaction is the formation of a triglyceride?
condensation
what are the bonds between the -OH groups of the glycerol and -COOH of the fatty acids called?
ester bonds
what are fatty acids made up of?
- a carboxylic acid group -COOH
- a long hydrocarbon chain of varying length
what are ester bonds?
strong covalent bonds
where do ester bonds form?
between the -OH groups of the glycerol and -COOH of the fatty acid
why are triglycerides not classed as polymers ?
- they are not a chain of repeating units
- they are made of two different types of molecule
how are triglycerides broken down ?
hydrolysis
give examples of the roles of triglycerides
- insulation
- energy
- protection
Why are triglycerides an excellent source of energy?
they have a high ration of energy storing carbon-hydrogen bonds to carbon atoms
why are triglycerides good for storage?
the have a low mass to energy ratio
why do triglycerides have no osmotic effects and do not effect the water potential in cells?
They are large, non polar molecules and insoluble in water
what are phospholipids composed of?
- A polar hydrophylic head
- a non polar hydrophobic tail
what is a phospholipid?
a lipids in which one of which has been substituted for a phosphate group
what is the hydrophylic head made of?
glycerol and phosphate
what is the hydrophobic tail made of?
fatty acids
what does hydrophobic mean?
repels water
what does hydrophylic mean?
attracts water
what is the test for lipids called ?
the emulsion test
explain how to conduct the test for lipids
- add ethanol to a sample
- shake to dissolve any lipid in the sample
- add water and shake gently
- if a lipid id present a milk white colour will appear
