Photosynthesis Tests. Flashcards
How do you provide light is required?
1) Decide on a method/grab a plant.
2) You can either place the plant in the dark and leave for at least 24 hours or cover part of one leaf and place in sunlight for several hours.
4) Remove covered leaf/plant from darkness for testing.
5) Add a couple of drops of iodine.
6) For the parts where no photosynthesis occurred/they will have to be the covered bits because there was no light, they will NOT get to be blue-black.
How do you prove oxygen is a product?
1) Cover pondweed with an upturned test tube & funnel.
2) Place in sunlight for several hours.
3) Wait until you have a full tube of
gas.
4) Light and put out a splint so it is
‘glowing’.
5) Place glowing split into tube of gas to test.
6) If oxygen is present, the splint will relight.
How do you test for starch?
1) Place leaf in a beaker with boiling water for
1 minute.
2) Remove leaf and place in a boiling tube of ethanol.
3) Place in water bath until green removed.
4) Wash with water to clean & soften.
5) Add a couple of drops of iodine.
6) Positive = Blue-Black.
How do you prove chlorophyll is required?
1) Place a variegated plant in the dark.
3) Leave for for at least 24 hours.
3) Place in sunlight for several hours.
4) Remove one leaf for testing.
5) Add a couple of drops of iodine.
6) Only parts with chlorophyll should turn blue-black.
How can you use carbon dioxide concentration to investigate rate of photosynthesis?
Carbon dioxide dissolves in aqueous solutions to form carbonic acid, which is used by algae during photosynthesis.
This results in a pH increase as the solution becomes less acidic. By measuring the rate of pH change using indicator solution, the rate of photosynthesis can be investigated.
