Biology demonstration manual: Presence of starch in leaves

Biology demonstration manual

		Table of contents
		Foreword
		Acknowledgements
		Bibliography
		Classification of living organisms
		The food chain game
		Growing peanuts
		Roots
		Root hairs
		Vascular bundles
		Presence of minerals in soil
		Necessity of sunlight
		Transport of water in plants
		Transpiration
		Presence of starch in leaves
		Pollination
		Seed dissemination
		Seed structure
		Cotyledons
		Necessity of water for germination
		Rainfall on leaves
		Growth curve of a plant
		Grafting
		Importance of ground cover
		Cell-tissue-organ-system-organism
		Length of the small intestine
		Enzymes
		The three food groups
		Three food groups homework
		Carnivore and herbivore teeth
		The food chain game
		Long capacity
		Model lung
		Blood circulation
		How physical activity affects heart and breathing rates
		Locomotion
		Antagonistic muscles
		Suction
		Fern reproduction
		Moss preservation
		Are yeast living organisms?
		Yeast
		Yeast budding
		Nitrogen fixing nodules
		Amoeba
		Bursting red blood cells
		Length of a ténia
		Model of a schistosome
		Adaptations
		Mountain formation
		Artesian well
		Bone structure
		Reflexes
		Test for glucose
		Test for starch
		Test for fats
		Test for proteins
		Cooling effect of sweat
		MICROSCOPE PREPARATIONS

Class: 6Ã¨me

Lesson: La nutrition des plantes

Rationale: Show presence of starch in leaves by boiling out the chlorophyll and then doing the iodine-starch test.

Materials:

leaves (Peanut leaves work fairly well. It's easier to extract chlorophyll from younger leaves.)

alcohol (available in pharmacies)

iodine (MIF kit)

Positive controls (ie. bread, patate douce)

Negative controls (ie. wood, chalk)

forceps

Procedure:

Preparation a day before class:

1. Put a glass of alcohol in a pan of boiling water.

2. Put leaves, picked on a sunny day, in boiling water for 30 seconds.

3. Then boil leaves in alcohol for about 20 minutes till the leaves are light green.

4. Dry leaves on paper inside of a book.

5. De-chlorophylled leaves are good for a couple of days.

6. Save the green alcohol to show the class the chlorophyll.

In class:

7. Demonstrate the iodine-starch test using both positive and negative controls. (See "Test for Starch", p. 30.)

8. Then add a couple drops of iodine to the de-chlorophylled leaf. Wait a minute and the leaf will turn black.

Source: Mackean Class Experiments in Biology, p. 34.