bio paper 6

Question 1

why is it better to correct several results

Answer 1

identify anomalous results

Question 2

test and result for starch

Answer 2

starch use iodine solution, turns blue black if positive negative if orange/brown

Question 3

test and result for protein

Answer 3

biuret
blue= neg
purple/ lilac= positive

Question 4

test and result for fats

Answer 4

ethanol emulsification test needs to add water as well
produces milky white precipitate if positive
neg= continues colourless

Question 5

test and result for reducing sugar

Answer 5

benedicts solution, must use warm water bath
rainbow closer to red= pos
closer to blue= neg

Question 6

test and result for vitamin c

Answer 6

dcpip
blue= negative
colourless= positive

Question 7

how do you test a leave for starch

Answer 7

drop into very hot/ boiling water for one minute (to destroy cell membrane so chlorophyll molecules can pass through)
drop into hot ethanol to remove dissolve the green chlorophyll
place leaf into water to rehydrate and soften the leaf so that it can spread out
drop iodine solution onto the leaf to test for starch