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design photosynthesis

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TITLE : factors affecting rate of photosynthesis Research question : What is the effect of light intensity on the rate of photosynthesis in Ananas Comosus leaf disc? Introduction: Photosynthesis is a chemical process whereby light energy is used to convert raw materials; water, carbon dioxide, to organic substances such as glucose and oxygen. Water vapour is also released to surrounding as waste product. Photosynthesis can be summarized as following: Carbon dioxide + water �� Glucose + Oxygen However, the rate of photosynthesis can be higher or lower depending on the factors that affect them; light intensity, temperature, concentration of carbon dioxide. This process occurs in chloroplast because it contains abundant green pigments called chlorophyll. These pigments are found to be in any parts of the plants that is green, including the leaves. Light intensity is one of the factors that largely affect photosynthesis because it is used to supply photons to the chlorophyll. When it reaches photosystems in chlorophyll, more electrons are excited and released to start off the process of photosynthesis. As a result, the rate of photosynthesis will increase gradually. ...read more.


4. 2 cm3 or the 20 cm3 sodium hydrogen carbonate inside the beaker is measured and poured into the same syringe. 5. The airs inside the syringe is pushed out and then, pull the syringe's plunger upwards while its nozzle is closed using a thumb. 6. All the leaf disks and sodium hydrogen carbonate solution inside the syringe is poured back into the beaker. 7. The content of the syringe is then poured into a beaker. The leaf discs are made to a single layer, rather than they are on top of one another. 8. The bulb is switched on and stopwatch is started immediately 9. The time taken by each leaf disc to float on the surface of sodium hydrogen carbonate solution is measured using stopwatch. 10. The experiment is required to be repeated with varying light intensity 11. All data are recorded and presented as below. Data Collection a) Qualitative Data 1. Air bubbles are produced from the leaf disks when the syringe's plunger is pulled outwards. 2. All of the leaf disks sink under the water when they are immersed in the sodium hydrogen carbonate solution initially. ...read more.


Ananas Comosus leaf has scattered distribution of chlorophylls while most of the chlorophylls is located at the under part and the rest at the upper part. Leaf disks are immersed in different orientation. Some of them are in upright position while the others are upside down. Thus, the rate of photosynthesis differs from one leaf to the other. All of the leaf disks immersed in the sodium hydrogen carbonate solution should have only one same orientation. In this case, we need to ensure that all of the lower parts of the discs face upward. Evaluation Conclusion When leaf discs are immersed in a sodium hydrogen carbonate solution (a source of carbon dioxide) and illuminated, the oxygen produced by photosynthesis causes the leaves to float. The time the leaves take to float can thus be used as an indirect measure of the rate of photosynthesis i.e. the more quickly flotation occurs, the faster the rate of photosynthesis. However this is true only until a certain point is reached. After the point is reached, the rate of photosynthesis will no longer increase but rather decrease. This is because there are other factors such as the denaturation of enzymes or cells. ...read more.

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