lipids

Question 1

what are lipids

Answer 1

macromolecules
contain carbon, oxygen and hydrogen
3 types - triglycerides, phospholipids and cholesterol

Question 2

triglycerides

Answer 2

one molecule of glycerol
3 fatty acids attached
ester bond between each fatty acid and glycerol

Question 3

ester bonds

Answer 3

formed by a condensation reaction
broken down by hydrolysis reaction
synthesis of triglycerides - esterification

Question 4

fatty acids

Answer 4

have long tails made of hydrocarbons
tails are hydrophobic
insoluble in water

Question 5

saturated fatty acids

Answer 5

no double bonds between carbon atoms in hydrocarbon tails

Question 6

unsaturated fatty acids

Answer 6

at least one double bond between carbon atoms, causes kink in chain

Question 7

phospholipids

Answer 7

one molecule of glycerol
2 fatty acids attached by ester bonds (hydrophobic)
phosphate group attached to glycerol (hydrophilic)

Question 8

cholesterol

Answer 8

hydrocarbon ring structure attached to a hydrocarbon tail
ring has a polar OH group attached to it

Question 9

functions of triglycerides

Answer 9

animals and plants - energy storage molecules
bacteria - energy and carbon store
good for storage - tails contain a lot of chemical energy so is released when broken down
insoluble

Question 10

function of phospholipids

Answer 10

found in cell surface membrane of all prokaryotes and eukaryotes
make up phospholipid bilayer
form a double layer with their heads facing outwards

Question 11

cholesterol

Answer 11

eukaryotic cells - strengthen cell membrane by interacting with bilayer
small flattened shape - can fit between phospholipids in bilayer
bind to phospholipids causing them to pack closer together
makes membrane more rigid