PLANT NUTRITION WORKSHEETS•OBJECTIVES:By the end of this topic you should:(a) Understand the importance of photosynthesis whereby green plants use chlorophyll toabsorb light energy and convert carbon dioxide and water into glucose, producing oxygenas a by-product.(b) Know that the rate of photosynthesis may be decreased by low temperature, shortageof carbon dioxide, low light intensity. (c) Know the uses made by plant cells of the glucose produced in photosynthesis.

•Discuss with your teacher or in small groups how plants feed.Decide whether each of these statements is TRUE or FALSE. Check your answers,

thencorrect any which are false:A. plants get all their food from the soil.

B. plants get water and mineral ions (e.g. nitrates) from the soil.

C. plants make all the substances they need by photosynthesis.

D. plants use heat energy from the sun to power photosynthesis.

E. some plant cells use a green pigment called chlorophyll to absorb light energy.

F. chlorophyll is found inside mitochondria in leaf cells.

G. plants can make food using light energy to combine carbon dioxide and water.

H. plants produce the waste gas hydrogen from photosynthesis.

I. plants can make sugars, starch, cellulose and fats from photosynthesis.

3. Write down the word equation for photosynthesis, and the balanced chemical equation below it.

•Read your textbook or support material on limiting factors for photosynthesis. Explain the term limiting factor:What are the 3 main limiting factors for photosynthesis?

Explain HOW and WHY each one limits photosynthesis:(i)________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________(ii)_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

(iii)______________________________________________________________________________ ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________•Identify and label different cellular and tissue structure of a dicotyledonous leaf.

A:__________________ B:____________________ C:__________________ D:____________________ E:__________________ F:____________________ G:__________________ H:____________________ I:__________________

•Experiment No. 1: Testing a leaf for starch.1. Take a leaf from a healthy plant and drop it into boiling water in a water bath. Leave it for about 30 seconds. (The length of time varies for different types of leaves.)2. Remove the leaf, which will be very soft and drop it into a tube of alcohol in the water bath. Leave it until all the chlorophyll has been dissolved out of the leaf.3. The leaf then now is brittle. Remove it from alcohol, and dip it into water again to soften it.

4. Spared out the leaf on a white tile, and cover it with iodine solution. A black colour shows that the leaf contain starch.

Note: Alcohol is very inflammable so it must not be heated directly over a bunsen flame.Questions:1. Why was the leaf put into boiling water?______________________________________________________________________________________________________________________________________________2. Why did the alcohol become green ?______________________________________________________________________________________________________________________________________________3. Why was the leaf put into alcohol after being put into boiling water?_____________________________________________________________________________________________________________________________________________________________________________________________________________________

•Experiment No. 2: To see if light is necessary for photosynthesis. 1. Take a healthy plant, growing in a pot. Leave it in a cupboard for a few days, to de starch it.2. Test one of its leaves for starch, to check that it does not contain any.3. Using a folded piece of paper or aluminum foil, a little larger than the leaf, cut out a shape. Fasten the paper or foil firmly over both sides of a leaf on your plant, making sure that the edges are held firmly together. Don’t take the leaf off the plant.4. Leave the plant near a warm, sunny window, and test it for starch. Make a labeled drawing of the appearance of your leaf after testing of starch.

Questions:1. Why was the palnt destarched before the beginning of the experiment?______________________________________________________________________________________________________________________________________________

2. Why was the part of the leaf left uncovered ?______________________________________________________________________________________________________________________________________________3. What do your results tell you about light and photosynthesis?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

•Experiment No. 3: To see if carbon dioxide is necessary for photosynthesis.1. De starch a plant.2. Set up your apparatus as shown in the figure. Take special care that no air get into the flasks.3. Rubber bung is smeared with Vaseline to make an air tight seal. 4. Leave the plant in a warm sunny window for a few days.5. Test each treated leaf for starch.

Note: Potassium hydroxide solution is used as carbon dioxide absorbent.Questions:1. Why was potassium hydroxide put in with one leaf, and water with the other?_____________________________________________________________________________________________________________________________________________________________________________________________________________________2. Which was the control?_______________________________________________________________________3.Why was Vaseline put around the tops of the flasks/______________________________________________________________________________________________________________________________________________4. What do your results suggest about carbon dioxide and photosynthesis?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

•Experiment No.4: To see if chlorophyll is necessary for photosynthesis.1. De starch a plant with variegated (green and white) leaves.2. Leave your plant in warm, sunny spot for a few days. 3. Test one of the leaves for starch.4. Make a drawing of your leaf before and after testing.

Questions:1.What was the control in this experiment?______________________________________________________________________________________________________________________________________________

2. What do your results tell you about chlorophyll and photosynthesis?_____________________________________________________________________________________________________________________________________________________________________________________________________________________

•Experiment No, 5: To show that oxygen is produced during photosynthesis.1. Set up the arraratus as shown in the fig. Make sure that the test tube is completely full of water.2. Leave the apparatus near a warm, sunny window for a few days.3. Carefully remove the test tube from the top of the funnel, allowing the water to run out, but not allowing the gas to escape.4. Light a wooden splint, and then blow it out so that it is just glowing. Carefully put it into the gas in the test tube. If it bursts into flame then the gas is oxygen.

Questions :1 . Why was this experiment done under water?_____________________________________________________________________________________________________________________________________________________________________________________________________________________2. This experiment has no control. Try to design one?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

• Glossary. (Muddled – sort them out!)1. Carbon dioxide Dissolves chlorophyll and decolorizes leaves in starch test2. Cellulose Gas needed for photosynthesis; limiting factor3. Chlorophyll Energy-rich storage compounds e.g. sunflower oil4. Chloroplast Cell wall polysaccharide; made from many glucose units5 .Ethanol Small structures inside leaf cells packed with chlorophyll6. Fats (oils) Turns blue-black when mixed with starch7. Glucose Green pigment which absorbs light energy for photosynthesis8 .Iodine solution Mineral ions absorbed from soil; needed to make proteins

9. Light energy Sugar made in plants by photosynthesis; used in respiration10 .Light intensity Waste gas produced by photosynthesis; used in respiration11. Limiting factor Absorbed by chlorophyll; needed for photosynthesis12. Nitrates Storage polysaccharide; made from many glucose units13. Oxygen Increasing this increases light energy; limiting factor14. Proteins A leaf containing yellow areas which lack chlorophyll15. Starch An independent variable which controls rate of photosynthesis16. Stencil Limiting factor; supplies heat energy for enzymes to work17 .Temperature Made from sugars and nitrates; needed for plant growth18. Variegated Leaf partly covered in foil, excluding light from covered areas

• Useful web links:http://www.purchon.com/biology/revision.htmhttp://www.wpbschoolhouse.btinternet.co.uk/page22/AQASciSyllRev/module01.htmhttp://www.sciencezone.org.uk/work.htmhttp://www.s-cool.co.uk/topic_index.asp?subject_id=17&d=0http://www.bbc.co.uk/schools/gcsebitesize/biology/greenplantsasorganisms/http://www.hotcourses.com/pls/hot_school/sn_revision.page_pls_revision_detail