lipids

Question 1

how is a triglyceride formed

Answer 1

by a condensation reaction of one molecule of glycerol (alcohol) and 3 molecules of fatty acids

Question 2

how many condensation reactions are required to form a triglyceride

Answer 2

3 condensation reactions so 3 water molecules are removed

Question 3

how many bonds are found in each triglyceride molecule

Answer 3

3 ester bonds

Question 4

how is water molecule removed

Answer 4

in a condensation reaction, H is removed from glycerol and OH is removed from fatty acid

Question 5

why is 1 triglyceride molecule not a polymer

Answer 5

its not made of the same monomers

Question 6

where are triglycerides usually found

Answer 6

in food (storage molecules)

Question 7

what do phospholipids do

Answer 7

form a cell membrane around the cell

Question 8

give other functions of lipids

Answer 8

-conduct heat slowly (so are good thermal and electric insulators)
-stored around delicate organs like liver and kidney
-similar to waxes however it contains alcohol

Question 9

compare the proportion of oxygen in lipids and carbohydrates

Answer 9

much less in lipids (C:H2:O)

Question 10

how are fatty acids an R group and give the 2 types

Answer 10

-because numbers of hydrogens and carbons can differ
-saturated and unsaturated

Question 11

what is a saturated fatty acid

Answer 11

-when the hydrocarbon chain has only single bonds between carbons, bonded to maximum numbers of hydrogen
-most likely to be solid at room temp because chains are packed together

Question 12

what is an unsaturated fatty acid

Answer 12

-when the hydrocarbon chain consists of at least one double bond between carbons, not holding maximum numbers of hydrogen possible
-most likely to be liquid at room temp

Question 13

why are unsaturated fatty acids likely to be liquid at room temp

Answer 13

sometimes the double bond causes a bend/kink that prevents the fatty acids from packing tightly, keeping them liquid.

Question 14

give the properties and their uses of a triglyceride

Answer 14

-ENERGY STORE = due to large ratio of energy-storing carbon-hydrogen bonds to number of carbons, a lot of energy is stored in molecule
-due to high ratio of hydrogen to oxygen atoms triglycerides act as a METABOLIC WATER SOURCE, so they can release water if they are oxidised, essential for animals in dry areas like camels
-triglycerides don’t affect water potential and osmosis because they are large and HYDROPHOBIC making them insoluble in water
-lipids have a relatively LOW MASS so a lot can be stored without increasing the mass if organism and without preventing restriction of movement

Question 15

how is a phospholipid formed

Answer 15

by 2 condensation reactions resulting in 2 ester bonds

Question 16

what is a phospholipid made up of

Answer 16

1 glycerol 2 fatty acids chain and a phosphate group (attached to the glycerol)

Question 17

give the properties of phospholipids

Answer 17

POLAR-the hydrophilic ‘head’ (phosphate group) can attract water as it is charged , so it’ll repel other fats
NON-POLAR-the fatty acid chain is known as the hydrophobic ‘tail’ and it repels water bc it has no charge but it will mix with other fats

Question 18

because of the properties of phospholipids, how will they arrange themselves in water

Answer 18

-they will arrange themselves in 2 layers called a bilayer
-hydrophobic fatty acids tails will face each other away from water
-hydrophilic heads are exposed to water

Question 19

what does a phospholipid bilayer form

Answer 19

a membrane structure which makes up the plasma membrane around cells / cell membrane