photsynthesis experiments

Question 1

how can you test for starch

Answer 1

plants convert glucose into starch
- take leaf and place in boiling water
- place leaf into boiling tube of ethanol to remove chlorophyll
- wash the leaf with water to remove ethanol and soften leaf
- add a few drops of iodine solution
- if starch is present iodine will turn from yellow-brown to blue-black

Question 2

how to prove chlorophyll is needed for photosynthesis

Answer 2

destarched variegated plant and leave in sunlight for several hours. test leaf for presence of starch

Question 3

how to prove light is needed for photosynthesis

Answer 3

destarched plant
cover one part of leaf with black card or tin foil
place in sunlight for several hours
test for starch

Question 4

prove CO2

Answer 4

destarched plant
place in polythene bag
add pot of soda lime
place plant in sunlight
test one leaf for starch

Question 5

prove oxygen is given off

Answer 5

place upturned test tube above an aquatic plant
place glowing splint inside tube
splint will relight