Write an activity starch in leaves in experiment
Answers
Answered by
3
Materials required:
bunsen burner, tripod stand, wire gauze(OR 90oC electric water bath OR hot plate)
250 cm3 beaker
boiling tube
anti- bumping granules
forceps
test tube holder
white tile
leaf to be tested (hibiscus leaves are excellent)
90% ethanol
iodine/potassium iodide solution
Procedure:
Remove a green leaf from a plant that has been exposed to sunlight for a few hours
Half-fill a 250cm3 beaker with water. Heat the water until it boils. Keep the water at boiling point.
Use the forceps to place the leaf in the boiling water. Boil for 2 minutes.
Turn off the Bunsen Burner. (If you are using a heat source without a naked flame - electric water bath or hot plate - this step is unnecessary.)
Place the boiled leaf in a boiling tube containing 90% ethanol.
Place the boiling tube in hot water and boil for 10 minutes or until the leaf decolourizes. ( It may be necessary to replace the ethanol)
Gently remove the leaf and wash with a fine trickle of cold tap water.
Spread the leaf evenly on a white tile.
Add a few drops of iodine/potassium iodide solution to the leaf and note any observations.
Observations/Results
The leaf was flaccid (soft) after being boiled in water
The ethanol changed from colorless to green
The leaf was brittle after being boiled in ethanol
The leaf become flaccid once more after being rinsed in cold water
After iodine solution was added...
Observation:
No color change (Iodine Solution remains brown)
Iodine/Potassium Iodide solution changed from brown to blue- black
Interpretation:
Starch is not present
Starch is present
“Hope this may help you..!!!”
bunsen burner, tripod stand, wire gauze(OR 90oC electric water bath OR hot plate)
250 cm3 beaker
boiling tube
anti- bumping granules
forceps
test tube holder
white tile
leaf to be tested (hibiscus leaves are excellent)
90% ethanol
iodine/potassium iodide solution
Procedure:
Remove a green leaf from a plant that has been exposed to sunlight for a few hours
Half-fill a 250cm3 beaker with water. Heat the water until it boils. Keep the water at boiling point.
Use the forceps to place the leaf in the boiling water. Boil for 2 minutes.
Turn off the Bunsen Burner. (If you are using a heat source without a naked flame - electric water bath or hot plate - this step is unnecessary.)
Place the boiled leaf in a boiling tube containing 90% ethanol.
Place the boiling tube in hot water and boil for 10 minutes or until the leaf decolourizes. ( It may be necessary to replace the ethanol)
Gently remove the leaf and wash with a fine trickle of cold tap water.
Spread the leaf evenly on a white tile.
Add a few drops of iodine/potassium iodide solution to the leaf and note any observations.
Observations/Results
The leaf was flaccid (soft) after being boiled in water
The ethanol changed from colorless to green
The leaf was brittle after being boiled in ethanol
The leaf become flaccid once more after being rinsed in cold water
After iodine solution was added...
Observation:
No color change (Iodine Solution remains brown)
Iodine/Potassium Iodide solution changed from brown to blue- black
Interpretation:
Starch is not present
Starch is present
“Hope this may help you..!!!”
Answered by
10
The presence of starch in leaves can be tested by Iodine test. When we remove chlorophyll from leaf by boiling it in alcohol and then put two drops of iodine solution, its colour change to blue indicates the presence of starch.
Similar questions