Ardrossan Academy Dead Earth Subtopic – Photosynthesis contd.

I will be successful if I can : Lesson Title: Testing a Leaf for Starch Learning Intention:. Name the solution used to test leaves for starch and the colour change it produces. Activity: I will be successful if I can : Safely test a leaf for Starch and remember the steps

Photosynthesis recap animation http://www.kscience.co.uk/animations/photosynthesis.swf

Photosynthesis Photosynthesis

GLUCOSE is produced during photosynthesis and stored as STARCH If a leaf has starch in it, it means photosynthesis has been taking place IODINE solution turns blue/black if starch is present

Testing a leaf for starch

Method - 2. PUT OUT THE BUNSEN BURNER Animation 1. Boil the leaf in water for 5 min (to soften the leaf) 2. PUT OUT THE BUNSEN BURNER 3. Use the glass rod to transfer leaf into boiling tube 4. Place boiling tube back into the hot water to boil the leaf in alcohol (to remove the green colouring) 5. Carefully lift the leaf out with glass rod and place in hot water to wash the leaf 6. Spread the leaf out on a dimple tile. 7. Test with Iodine solution Animation 1. Boil in water - (water in beaker) 2. Boil in alcohol 3. Rinse alcohol off leaf 4. Test leaf with Iodine solution - (Bunsen switched off !! )

IF the iodine turns blue/black THEN the leaf has starch. Starch present Starch absent In the presence of light green plants are able to make starch (food) in their leaves

What conditions do you think are needed for photosynthesis? Aim To investigate the conditions required for photosynthesis What conditions do you think are needed for photosynthesis?

Before testing for starch After testing for starch Starch present Condition missing Before testing for starch After testing for starch Starch present (yes/no) None (control) light Chlorophyll Carbon dioxide dark

Method - 2. PUT OUT THE BUNSEN BURNER Animation 1. Boil the leaf in water for 5 min (to soften the leaf) 2. PUT OUT THE BUNSEN BURNER 3. Use the glass rod to transfer leaf into boiling tube 4. Place boiling tube back into the hot water to boil the leaf in alcohol (to remove the green colouring) 5. Carefully lift the leaf out with glass rod and place in hot water to wash the leaf 6. Spread the leaf out on a dimple tile. 7. Test with Iodine solution Animation 1. Boil in water - (water in beaker) 2. Boil in alcohol 3. Rinse alcohol off leaf 4. Test leaf with Iodine solution - (Bunsen switched off !! )

Before testing for starch After testing for starch Starch present Condition missing Before testing for starch After testing for starch Starch present (yes/no) None (control) light Blue/black yes Chlorophyll Some blue/black, some brown some Carbon dioxide brown no dark Green Green white Green Green

Conclusion I found out that . . . . (refer back to your aim) Carbon dioxide, light and chlorophyll are needed for photosynthesis to take place.

Lesson 2 - Learning Intentions Through practical work, name the conditions required for photosynthesis to take place

POSTER Title – ‘Do plants need chlorophyll / light / carbon dioxide for photosynthesis’ Method, including diagrams, of how you carried out the experiment Results – what colour did the iodine test produce Conclusion, what do plants need for photosynthesis. Word Equation