1. LI :To investigate the presence of starch in leaves
Testing leaves for Starch
LI :To investigate the presence of starch in leaves

2. What is photosynthesis?

3. Photosynthesis is the process by which green plants produce their own food

4. Photosynthesis Equation
Light energy
Carbon Dioxide
Water
GLUCOSE
Oxygen

5. Plants make their own food - Glucose
Glucose is a simple sugar made during photosynthesis in green plants
Glucose can be stored or used by the plant as an energy source

6. Glucose
Used up by the plant to grow
Stored as Starch

7. We can test leaves for the presence of starch using iodine solution…
Starch absent
Starch present

9. Stage 1
Boil water in the beaker using the bunsen and collect leaf disc to put into boiling water
Leave to boil for 5 minutes
While you are waiting……
Fill in worksheet

10. Stage 2 Turn off the Bunsen – IMPORTANT
Bring your boiling tube to the front and collect ethanol
Remove leaf from water and put it in the ethanol. Put the boiling tube back into the beaker of hot water and leave for 5 minutes
While you are waiting….
continue to fill in the worksheet

11. Stage 3 Remove leaf disc from the ethanol
Rinse the leaf disc in the beaker of hot water
Place the leaf disc on the dimple tray
Test for starch using iodine solution
Record results on the worksheet

12. Discussion of the results
What colour did the leaf go?
What did this tell us?
Has photosynthesis occurred in the leaf?

13. Teacher demo

14. No starch present Plant kept in the dark
Plants need sunlight for photosynthesis to occur

15. Plant starved of carbon dioxide
No starch present
Plants need carbon dioxide for photosynthesis to occur

16. Variegated leaf
Plants need chlorophyll for photosynthesis to occur

17. What have we learned today?
Success Criteria:
I can state that green plants make their own food which may be stored as starch.
I can successfully carry out an experiment to test leaves for starch
I can name the limiting factors in the process of photosynthesis.