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Why did leaf had to be boiled in ethanol when testing leaf for starch?
Wiki User
∙ 11y ago
Ethanol dissolves chlorophyll hence further phtosynthetic activity is stopped in the abscence of light and the leaf becomes transparent (colorless). the colorless leaf takes better stain with iodene while testing for the presence of starch.
Wiki User
∙ 11y ago
Wiki User
∙ 12y agoto remove the chloroplast and it will dissolve in the alcohol.
Wiki User
∙ 12y agoIt is to remove the chloroplast and dissolve in the alcohol and turn it green.
Wiki User
∙ 12y agoto remove the chlorophyll of the leaf or to make it uncolored
Wiki User
∙ 11y agowe do boil leaf in water and alcohol before performing starch test so that the green color(due to chlorophyll) of the leaf is removed.
Anonymous
Alcohol is used on green leaf to test starch because removal of chlorophyll from leaf is done by boiling of alcohol .
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When testing a leaf for starch why is it rinsed in cold water after it is boiled?
After the leaf has been placed in ethanol it becomes very brittle. It is then rinsed in cold water so as to soften it and makes it more manageable for the addition of iodine.
What is the role of iodine in testing a leaf for starch?
A hot bath of ethanol decolorizes the leaf by washing out the chlorophyll. If the leaf is not decolorized, you cannot see the blue-black stain that results from the iodine reacting with the starch.
What is the purpose of covering the leaf with iodine?
if you cover a boiled leaf in iodine you can see how much starch is in the leaf
What is the method for testing a leaf for starch?
1. Testing leaves for starch After photosynthesis, green plants store glucose as starch in their leaves. 2. What you will test. You will test 2 leaves: One from a plant left in the light . One from a plant kept in the dark . 3. Put the 2 leaves in boiling water to kill them 4. Place the leaves in a boiling tube with ethanol 5. wait until all the green colour disappears from the leaves 6. Remove the leaves 7. Wash the leaves 8. Spread the leaves out on a white tile 9. carefully add iodine to the leaves 10. Wait a few minutes and note the colour of the leaves. The leaf exposed to lightd will turn blue-black while the one in the dark will remain colourless.
Why do you need to remove chlorophyll from a leaf when testing for starch?
Chlorophyll has a function of converting starch into glucose and other simpler plant products.Thats why we have to remove cholorphyll before starting a test for 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.
When testing for starch why the leaf is boiled?
to denature the enzymes going to kill the leaf
When testing a leaf for starch why is it rinsed in cold water after it is boiled?
After the leaf has been placed in ethanol it becomes very brittle. It is then rinsed in cold water so as to soften it and makes it more manageable for the addition of iodine.
A leaf was taken from a plant boiled with ethanol and tested with iodine solution what is it tested for?
Starch, I think, because iodine solution is the test for starch.
What is the role of iodine in testing a leaf for starch?
A hot bath of ethanol decolorizes the leaf by washing out the chlorophyll. If the leaf is not decolorized, you cannot see the blue-black stain that results from the iodine reacting with the starch.
Why does leaf turn blue black when boiled in ethanol first then iodine?
Boiling in ethanol strips the leaf's waxy outer coating off, then the iodine turns it blue black because it's reacting to the presence of starch, a product of photosynthesis.
What is the purpose of covering the leaf with iodine?
if you cover a boiled leaf in iodine you can see how much starch is in the leaf
What did you see on the leaf in the test tube when testing for starch?
Use iodine to test a leaf for starch | Plant Physiology | Biology
Why does leaf turn light green when boiled in ethanol?
add the leaf to boiling ethanol in a water bath for a few minutes (the boiling ethanol dissolves the chlorophyll and removes the green colour from the leaf - it turns white so it is easy to see the change in colour) wash with water to rehydrate and soften the leaf
When a leaf becomes crispy after being boiled in ethanol how do you remove it?
by immersing it in a hot water bath
How do you carry out to test for presence of starch?
Half fill a beaker with boiling water and add a large test tube that is a quarter full of ethanol. Allow the ethanol to come to a boil. Do not heat the ethanol in a Bunsen burner flame. This is not safe because ethanol is highly flammable. Take a leaf that has been sitting in good light for at least a few days, and soften in the boiling water for ten seconds or so. Then add to the ethanol, and allow to boil for about a minute until all the color disappears from the leaf. Remove the leaf from the ethanol. Put it back in the hot water to soften for 10 seconds. Spread the leaf out on a white tile and use the iodine solution to test for starch a blue-black color indicates starch is present.
When testing a leaf for starch why do you have to boil the leaf in water first?
so the waxy cuticles can rub off the surface of the leaf. a leaf has a cell wall and if you did not put the leaf in the boiling water it would not break down so therefore you would not be able to do a proper starch test on the leaf so the answer to this question is to break the cell wall down so you can test for starch properly i hope i helped you :) yeap
