Testing A Leaf For Starch [PDF]

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Testing a Leaf For Starch iodine solution



Method 1. Take the two leaves and cut the end off the one that has been in the dark, so you can remember which is which.



2. Turn off the Bunsen burner. Half fill a test tube with ethanol. Place two leaves in it using forceps. Place the test tube into the beaker of hot water and leave it for 5 minutes. hot water ethanol



Bunsen burner turned off



3. Place both leaves in a beaker of boiling water for one minute.



4. Take the leaves out of the test tube and wash them with tap water.



5. Place the leaves on a petri dish and put a few drops of iodine solution on them. If a blue-black colour appears, there is starch in the leaf.



1. What substance makes iodine solution turn blue-black?



2. What process produces this substance?



3. Write down what happened. What colours did each leaf go when iodine solution was added? Did all of the parts of the leaves change colour?



4. The diagrams below show different leaves in different conditions. In the diagrams below shade in the parts that you think will turn blue-black when iodine solution is added.



This leaf is all green and was grown in the light.



This leaf is all green and was grown in the dark for 48 hours.



This leaf is all green but had a strip of aluminium foil covering part of it. It was grown in the light.



This leaf is dead. It is brown. The plant it was on was growing in the light.



Testing different food sources for the presence of Starch Food source



Final Conclusion:



Result



Conclusion



Structure of a seed Draw and label the different parts of a seed and give their functions:



Arrange the different stages shown below in the right order:



What are the factors needed for germination? 1. 2. 3.



Complete the worksheet by stating if the seeds in each of the following conditions would germinate or not. Experiment



Expected result



Reason



Conclusion



Overall conclusion:



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