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Aim: To find out if light is needed for the production of starch through photosynthesis.
Hypothesis: Light is needed for Starch production in a Geranium leaf.
Apparatus: 2 100 mL beakers 1 Petri dish 1 Geranium leaf
2 Paper Clips 1 Piece of Foil Boiling water
Methylated Spirits iodine Hot Plate
Method
1. Cover half of the geranium leaf with foil, using two paperclips to secure it on.
2. Leave in direct light for 1 week.
3. Uncover the leaf and place it in a 100mL beaker
4. Put boiling water in the beaker just enough to cover the leaf and leave for 30 seconds.
5. Place the leaf in the other 100mL beaker, cover with methylated spirits. Use the hot plate to keep the methylated spirits just below boiling point. Keep at this temperature until the leaf has lost all its green colour.
6. Place the leaf in the petri dish and cover with iodine.
Watch the colour difference between both sides. Record the results (see below). The dark colour is the presence of starch
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∙ 12y ago
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What happens if starch is present in leaf?
The presence of starch in plants indicate that photosynthesis has occurred. The process of testing the presence of starch uses iodine solution that turns to blue-black on a positive test.
How do you explain when we add starch solution saliva dilute alkali and did not presence of starch and presence of glucose?
The enzyme amylase in the saliva broke the starch down into glucose.
What are the food tests for starch?
Iodine turns blue in the presence of starch.
What indicates the presence of starch in the food samples?
blue-black color indicates the presence of starch
Why did the leaf turn brittle in testing a leaf for starch?
The leaf turns brittle during the testing the leaf for starch because the ethanol extracts the all water content from the leaf.
How can you prove by experiment to show that starch is produced in the presence of sunlight?
Aim of an experiment to show that starch is produced in the presence of sunlight
What is the food test for starch?
It is simply called the Starch test which is the process of testing something for the presence of starch. Add Iodine solution to whatever is it you're testing and a dark blue/black color indicates the presence of starch
What would you use to test starch?
A classic way of testing for the presence of starch is to add a drop of tincture of iodine. If the brown solution turns violet then starch is present.
Why must leaves be exposed to sunlight for some time before testing for starch?
Because they need the presence of chlorophll in them
What happens if starch is present in leaf?
The presence of starch in plants indicate that photosynthesis has occurred. The process of testing the presence of starch uses iodine solution that turns to blue-black on a positive test.
How do you explain when we add starch solution saliva dilute alkali and did not presence of starch and presence of glucose?
The enzyme amylase in the saliva broke the starch down into glucose.
What are the food tests for starch?
Iodine turns blue in the presence of starch.
Why did each of the solutions turn iodine blueblack at the start of the experiments?
Iodine is famous for testing of the presence of starch. I would assume starch is present in the solution, therefore iodine would turn blue. Originally, the colour of iodine solution is brown.
What indicates the presence of starch in the food samples?
blue-black color indicates the presence of starch
What color change does starch indicator solution make in the presence of starch?
Iodine turns it purple in the presence of starch. :D~PiNkBuN17 Aka Aisha
What turns color in the presence of strach?
In the presence of starch, iodine turns purple.
What is used to test for the presence of lodine?
Starch.
