2. Lipids

Question 1

triglycerides are a kind of

Answer 1

lipid

Question 2

structure of a triglyceride

Answer 2

1 molecule of glycerol with 3 fatty acids attached to it

Question 3

fatty acid molecules have long tails made of

Answer 3

hydrocarbons

Question 4

fatty acid tails are

Answer 4

hydrophobic (repel water molecules

Question 5

fatty acid tails make lipids

Answer 5

insoluble in water

Question 6

basic structure of a fatty acid

Answer 6

COOH attached to R group

variable R group is hydrocarbon tail

Question 7

triglyerides are formed by

Answer 7

condesnation reactions

Question 8

bond between a glycerol and fatty acid is an

Answer 8

ester bond

Question 9

saturated fatty acid

Answer 9

no double bonds between c atoms

Question 10

unsaturated fatty acid

Answer 10

at least 1 double bond between c atoms

Question 11

how are phospholipids similar to triglycerides

Answer 11

same except 1 fatty acid is replaced by a phosphate group

Question 12

phospholipid phosphate head is

Answer 12

hydrophilic (attracts water)

Question 13

phospholipid 2 fatty acid tails are

Answer 13

hydrophobic (repel water)

Question 14

triglycerides are mainly used as

Answer 14

energy storage molecules

Question 15

why are triglycerides effective as energy storage molecules

Answer 15

1. long hydrocarbon tails of fatty acids contain lots of chemical energy = lots of energy released when broken down
2. insoluble so dont affect water potential of the cell and cause water to enter by osmosis which would make them swell.

Question 16

triglycerides clump together as

Answer 16

insoluble droplets in cells because fatty acids are hydrophobic
tails face inwards shielding themselves from water with their glycerol heads

Question 17

phospholipids make up

Answer 17

bilayer of cell membrane (which controls what enters and leaves cell)

Question 18

phospholipids ad bilayer of cell membrane

Answer 18

heads hyrdrophillic and tails hydrophobic = form a double layer with their heads facing out toward the water on either side
centre of bilayer is hydrophobic = water soluble substance cant easily pass through (membrane acts as a barrier to these substances

Question 19

how does the phospolipid bilayer act as a barrier to water soluble substances

Answer 19

centre of bilayer is hydrophobic = water soluble substance cant easily pass through (membrane acts as a barrier to these substances

Question 20

the test for lipids

Answer 20

emulsion test

1. shake sample with ethanol for about a minute so it dissolves then pour solution in water
2. any lipid will show up as a milky emulsion
3. more lipid = more noticeable the milky colour.