lipids and their functions Flashcards
(19 cards)
why are lipids good for energy storage
-release a lot of energy per gram when oxidised so they store a lot of energy
-do not dissolve in water, so no effect on osmosis or water potential
why can saturated fats be stored under the skin of animals
solid at room temperature so can be stored without moving
why are lipids good for water proofing
-oils are hydrophobic so they make water run off fur, skin or feathers
-oil on the skin also reduces water loss by evaporation
-waxes are lipids found in the cuticle of plants- this reduces water loss
why are lipids good for insulation
fat is a poor conductor of heat, so fat under the skin provides thermal insulation
Myelin is a lipid that provides electrical insulation around the nerves
what makes a triglyceride more fluid
if it has unsaturated fatty acids in (more useful for water proofing)
What is the structure of a phospholipid
hydrophilic head and 2 hydrophobic tails
2 fatty acids and a phosphate attached to a glycerol
what do phospholipids do in water
form a phospholipid bilayer
which is the basis if cell membranes
the double layer of hydrophobic tails acts as a barrier to the movement of water, so makes membranes selectively permeable
what is cholesterol
-lipid produced in animals
-cholesterol in the cell membrane regulates how fluid the membrane is - usually make it less fluid
what do lipid do
-don’t mix with water
-hydrophobic
what are lipids solid at room temp called
fats
what are lipids liquid are room temperature called
oils
what rare triglycerides
group of lipids
-1 glycerol molecule
-3 fatty acids
what is the structure of fatty acids
-carboxylic acid group
-residual group
does the r group in fatty acid bond with water
yes but doen’t mix with other lipids
what does it mean if an r group does/ doesn’t have a double bond between two of its carbons
no double bond= saturated
1 double bond=unsaturated
more than 1 double bond= polyunsaturated
how do fatty acids combine with glycerol
in a condensation reaction to make a monoglyceride and water
how are is monoglyceride bonded together
with an ester bond
how are triglycerides made
by adding 2 more fatty acids joined at the HO groups
what do the properties of triglycerides depend on
the fatty acids used to make it
