lipids

Question 1

what is a lipid ?

Answer 1

fats, waxes and oils

Question 2

what is the most common type of lipid ?

Answer 2

the triglyceride

Question 3

what are lipids used for ?

Answer 3

• for storage
• high energy store
• production of metabolic water
• insulation
• waterproofing

Question 4

why can it be used for storage ?

Answer 4

they do not affect water potentials and osmosis as they are large and hydrophobic, making them insoluble in water so they can be stored in a compact way

Question 5

why can it be used for a high energy store ?

Answer 5

lipids have a high proportion of hydrogen atoms relative to oxygen so respiration of lipids yields more energy

Question 6

why can it be used for the production of metabolic water ?

Answer 6

because some water is produced as a final result of respiration
as the triglycerides can release water if they are oxidised

Question 7

what are the 2 types of insulation lipids can be used for ?

Answer 7

mechanical insulation- prevents impact
- thermal insulation

Question 8

what does it mean when a molecule is saturated ?

Answer 8

there is no double carbon to carbon bond
there are only single bonds between he carbons

Question 9

what does it mean when a molecule is unsaturated ?

Answer 9

it contains at least one double carbon to carbon bond between the carbons

Question 10

what is a lipid made out of ?

Answer 10

glycerol and fatty acid

Question 11

what does a triglyceride contain ?

Answer 11

glycerol
3x fatty acids
3x ester bonds

Question 12

on what does the properties of lipid depend upon?

Answer 12

the length of the fatty acid tails and the saturation

Question 13

what are all lipids ?

Answer 13

insoluble in water

Question 14

what is the test for a lipid ?

Answer 14

emulsion test
- lipid + water + ethanol + shake = cloudy white emulsion

Question 15

where are phospholipids found in ?

Answer 15

in cell membranes

Question 16

what do phospholipids contain ?

Answer 16

a phosphate group
glycerol
2 fatty acid tails

Question 17

How are lipid s made ?

Answer 17

the 2 fatty acids bonds to the glycerol via 2 condensation reactions resulting in 2 ester bonds

Question 18

at does hydrophilic mean ?

Answer 18

can make interactions with water

Question 19

how are triglycerides made ?

Answer 19

triglycerides are formed via the condensation between one molecule of glycerol and three molecules of fatty acids
so 3 condensation reactions occur to get 3 fatty acids

Question 20

what is the R group ?

Answer 20

the R group are fatty acids which can be saturated or unsaturated

Question 21

what can the hydrophilic head of a phospholipid do ?

Answer 21

it can make interactions with water as it is charged so it repels other fats

Question 22

what is the fatty acid chain known as ? and why ?

Answer 22

known as the hydrophobic tail as it repels water but will mix with fats

Question 23

what is it called if the phospholipid has 2 charged regions ?

Answer 23

it means that it is polar

Question 24

how are the phospholipids positioned in water?

Answer 24

in water they are positioned so that he heads are exposed to water and the tails are not

Question 25

what kind of structure do the phospholipids form in water ?

Answer 25

they form a phospholipid bilayer membrane structure which makes up the plasma membrane around cells