Importance Of Plants D. Crowley, 2008

Importance Of Plants To know why plants are useful to animals

Plants Crosswords  Complete the plants crossword

Plants Crosswords

Atmosphere How do plants produce their own food?  Photosynthesis carbon dioxide + water → glucose + oxygen Why is oxygen important?  Respiration oxygen + glucose → carbon dioxide + water light + chlorophyll

Respiration  Respiration is the release of energy (from glucose) in our cells (requires oxygen)  Animals and plants respire!  In the light plants respire, but produce the oxygen for this to occur via photosynthesis  In the dark plants still respire, however they do not produce any oxygen (as no photosynthesis takes place) meaning they also need to use the atmospheric oxygen

Food  As well as providing the oxygen needed for respiration by animal and plant cells, plants also store the food they make from photosynthesis as starch  Plants provide food in many different forms, including from the: - Leaf Stem Roots Seeds Fruit

Food  Your task is to look at a variety of foods from a plant, and decide from which part of the plant it is – record your results

Starch Test  As a class we are going to test each of the parts of the plant for the presence of starch  Iodine goes from orange / brown → dark blue / black if starch is present  Boil the plant tissue, and place in some ethanol (leave for 5 minutes, then rinse off the ethanol). Take a dropping pipette and add some iodine to the part of the plant, noting what happens

Starch Test

Food Store  Glucose is turned into starch, and is stored in roots, stems and leaves  Why is this done?!  It is stored in these areas so the plant cells can still respire, even if photosynthesis does not occur (starch is insoluble)  Some glucose is turned into lipids for storing in seeds  Some plants also store a large amount of starch in their roots over winter, allowing new plants to grow the following spring (e.g. potato and carrot plants)  Fruits also contain glucose to encourage animals to eat the fruit (helping disperse the seeds)

Benefit  Plants store their food not for the benefit of animals, but for the benefit of themselves Food is stored: -  So it can be used when photosynthesis cannot take place  As an energy store for harsher times  As an energy store for the seeds when they germinate  As a bribe to attract animals (helping with seed dispersal)

Plants & Photosynthesis  Using the sheet, cut out the key points and stick them in your book, making a revision page about photosynthesis