2.1.2 lipids Flashcards
what are the elements that make up lipids?
C H O P
what are triglycerides made up of?
1 glycerol
3 fatty acids
are triglycerides saturated or unsaturated?
can be both
what bonds do triglycerides have?
ester bonds
are plant triglycerides saturated or unsaturated?
unsaturated
can’t pack together as tightly
weaker intermolecular bonds so often oils at room temp
what is it called if a triglyceride has one double bond?
monounsaturated
what is it called if a triglyceride has more than one double bond?
polyunsaturated
how can triglycerides be used as an energy store?
respiration of fats releases 3x more energy in the form of ATP than glucose but can only respire when there’s oxygen
respiration of fats releases more water
how can triglycerides be used for insulation?
stored in a layer of adipose cells under the skin
acts as a barrier to heat loss
blood diverted to capillaries under the adipose layer to prevent heat loss from the skin
aquatic animals have blubber which prevents cold shock in the ocean
how can triglycerides be used as lubricant between our organs?
thin layer which acts as a shock absorber
minimises friction from rubbing
what are the uses of triglycerides?
insulation
energy store
lubricant between organs
what elements are phospholipids made from?
1 glycerol
2 fatty acids
a phosphate group
what is hydrophobic and what is hydrophilic in the phospholipid?
phosphate head is hydrophilic
fatty acid tails are hydrophobic
how do phospholipids form the cell membrane?
a phospholipid bilayer
tails pointing inwards heads pointing outwards
why is the bilayer fluid and what does it mean?
no bonds between tails and heads
molecules can move sideways freely allowing cell membrane to change shape
what shape is the cholesterol in?
rings
what does the cholesterol do?
helps to stabilise the bilayer when it’s too cold or warm
what does cholesterol do when the bilayer is too warm?
prevents membrane from becoming too fluid by attracting tails towards itself because it is hydrophobic
what does cholesterol do when the bilayer is too cold?
keeps fatty acid tails from packing together too tight allowing membrane to stay fluid and prevent it from fracturing
