1.2- Lipids

which elements do lipids contains?

C,H, O

what are lipids and examples?

large and varied group of non polar molecules that are insoluble in water, but dissolve easily in inorganic solvents

e.g fats (solids) and oils (liquids)

what are triglycerides?

glycerol molecule + 3 fatty acids

joined by ester bonds

formed by condensation reaction

saturated

only single bonds between carbons in hydrocarbon chain

unsaturated

double bond between carbons in hydrocarbon chain

why are triglycerides not classed as polymers?

not made up of repeating units,but one molecule of glycerol and 3 fatty acid groups

what are three properties of triglycerides?

high ratio of energy storing carbon-hydrogen bonds to carbon atoms and so excellent source of energy

low mass to energy ratio- good storage molecules as sm energy can be stored in small volume

large, non polar molecules

insoluble in water- no osmotic effect

what do phospholipids consist of?

polar/hydrophillic head (glycerol + phosphate) - attracts water

non polar/hydrophobic tails (fatty acids) - repels water

phospholipids are.. and they form..

polar due to two charged regions

forms phospholipid bilayer- makes up plasma membrane around cells

what does the bilayer act as a barrier to and what does it allow to pass?

acts as barrier to polar/water soluble/large molecules thru

allow non polar/lipid soluble/small molecules thru

what is the emulsion test of lipids?

add ethanol, shake

add water, shake

white emulsion forms

draw the structure of a phospholipid bilayer