Photosynthesis Lesson Starter in your jotter Write down

Lesson Starter (in your jotter) • Write down the equation for photosynthesis • What

Today we are going to: • Discuss what happens to the products of photosynthesis

During photosynthesis. . • Plants make OXYGEN and GLUCOSE. • Oxygen leaves the cell

Glucose The plant converts the glucose into the STORAGE molecule called STARCH Starch Glucose

Testing for Starch • We can test whether a plant has been PHOTOSYNTHESISING by

Before we test the leaf. . • Plant cells are WATERPROOF and their CELL

EXPERIMENT Boil the leaf in water for two minutes (this kills the cell and

EXPERIMENT Make sure the Bunsen burner is turned off- ethanol is extremely flamable •

EXPERIMENT • The leaf should now be pale in colour • Rinse it in

Instructions- work in pairs 1. Set up a tripod stand, Bunsen burner and a

Iodine • In the presence of STARCH, IODINE will turn from yellow/orange to a

Complete page 7 in your photosynthesis booklet

Complete homework task on page 4 for me to collect in and check tomorrow

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Photosynthesis

Lesson Starter (in your jotter) • Write down the equation for photosynthesis • What would happen if one of the RAW MATERIALS for photosynthesis wasn’t present? • What happens to the OXYGEN which is produced during photosynthesis?

Today we are going to: • Discuss what happens to the products of photosynthesis • Learn how to test for starch • Carry out the “testing for starch” experiment

During photosynthesis. . • Plants make OXYGEN and GLUCOSE. • Oxygen leaves the cell What does the glucose do?

Glucose The plant converts the glucose into the STORAGE molecule called STARCH Starch Glucose

Testing for Starch • We can test whether a plant has been PHOTOSYNTHESISING by testing for the presence of STARCH • We use IODINE to test for starch.

Before we test the leaf. . • Plant cells are WATERPROOF and their CELL WALL makes it difficult for the chemical (IODINE) to get through • We need to PROCESS the leave before we can do a starch test

EXPERIMENT Boil the leaf in water for two minutes (this kills the cell and softens the cell wall)

EXPERIMENT Make sure the Bunsen burner is turned off- ethanol is extremely flamable • Use the heat from the boiling water to heat the leaf in a test tube of ethanol • This removes the chlorophyll - you will notice the ethanol turning green

EXPERIMENT • The leaf should now be pale in colour • Rinse it in the boiling water • Spread the leaf on the white tile and add a few drops of iodine to it • What do you see happening?

Instructions- work in pairs 1. Set up a tripod stand, Bunsen burner and a beaker filled with 100 mls of water and place the leaf in the water- I will come and light the Bunsen 2. Boil the leaf in the water for 2 minutes 3. TURN THE BUNSEN BURNER OFF 4. Place the leaf in a test tube of ethanol then place the test tube in the beaker of boiling water- you will notice the ethanol starting to go green 5. Take the leaf out of the ethanol and spread it across the white tile 6. Add a few drops of iodine What do you notice?

Iodine • In the presence of STARCH, IODINE will turn from yellow/orange to a blue/black colour Iodine remains yellow No Starch present NO PHOTOSYNTHESIS Iodine turns blue/black Starch present PHOTOSYNTHESIS has taken place

Complete page 7 in your photosynthesis booklet

Complete homework task on page 4 for me to collect in and check tomorrow (Tuesday 1 st of September)