1. Glucose Production Noadswood Science, 2012

2. Glucose Production To understand how plants store and use the glucose produced during photosynthesis Monday, August 10, 2015

3. Equations The word equation for photosynthesis is carbon dioxide + water  glucose + oxygen The symbol equation for photosynthesis is 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2

4. Glucose & Starch During photosynthesis glucose is produced (a simple sugar) However, plants cannot store glucose, so they convert it into starch (many small glucose molecules are joined together) Starch is insoluble, meaning it can be stored easily (when you wash some rice you can see the starch wash off)

5. Glucose Glucose can be used to make long chains of starch… Glucose molecules Starch molecule This glucose is then used by the plant as a store of energy and some of it may be used for respiration The energy released from respiration can be used to make amino acids or to build up fats and oils as a food store in seeds

6. Proteins Glucose is combined with nitrate ions (NO 3 - ) (absorbed from the soil) to make amino acids which are then made into proteins…

7. Starch Test How can we test for starch? How can we relate the presence of starch to the amount of photosynthesis taking place? Iodine tests for starch – it turns blue/black in the presence of starch If a plant photosynthesis a lot, then there should be more starch present (as more glucose would have been made and converted into starch)

8. Experiment Your task is to look at two different types of leaf –one normal leaf, and one which has been kept in the dark You need to find out how much starch is present in each leaf… Follow the leaf starch experiment worksheet

9. Starch Experiment

10. Boiling & Ethanol Why do we need to boil the leaf first, and then add it to the ethanol? Boiling the plant damages the cell wall, and the ethanol extracts the chlorophyll from the leaf allowing us to test if any starch is present

11. Explanation Explain your results for the leaf in the light and the leaf in the dark The leaf in the light has a good store of starch (photosynthesis has taken place, converting the glucose produced to starch) The leaf in the dark cannot photosynthesize, but has been respiring (using up the starch supply)

12. Storage Why store the glucose as starch? Remember, the starch is insoluble, so the plant can store it conveniently without it getting dissolved within the cell which is much more convenient than the soluble glucose

13. Minerals How do plants absorb the minerals they need? Roots are adapted to absorb the minerals needed to remain healthy (although some plants have adapted some special ways to get more minerals, e.g. a Venus fly trap) Venus fly traps often live in areas where minerals are scarce – to compensate they can trap and digest insects, getting valuable minerals from them

14. Minerals There are 3 essential minerals: - Nitrates – needed for protein manufacture Phosphates – needed for respiration and photosynthesis Potassium – needed for enzymes involved in respiration and photosynthesis Iron and magnesium are also needed in trace amounts for chlorophyll production

15. Photosynthesis