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How does changing the temperature affect the rate of Photosynthesis?

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How does changing the temperature affect the rate of Photosynthesis? Photosynthesis is a necessary process which occurs in green plants, where the plant produces oxygen and makes food, taking place in the chloroplasts that contain chlorophyll. The chlorophyll absorbs the sunlight, and with that sunlight, water and carbon dioxide combine to make sugar and oxygen. The formula for this process is: 6CO2 + 6H2O > C6H1206 + 602 This process, photosynthesis, requires several important elements in order to occur. The factors which must be controlled are: temperature, light intensity, pH, light colour, H20, concentration of CO2 and amount of chlorophyll. When or if one of these factors is increased, the rate of photosynthesis will increase, though only to a certain point - the rate of photosynthesis though, could still increase, but not due to an increase in that same factor. In order for glucose to be made during photosynthesis, water's split into oxygen and hydrogen molecules. This is done by the enerrgy absorbed by the sun, following, the hydrogen must combine with the carbon dioxide to produce glucose. Without the sunlight, eventually the hydrogen would combine with the CO2, though it'd take a far longer time. A catalyst is needed to increase the rate of the process. In this case, the catalyst is enzymes. ...read more.


I cut roughly 6cm of elodea underwater, cutting the stem diagonally. I anchored a paper clip to the end which had not been cut. The piece of elodea was then placed into the water-filled test tube, ensuring the diagonally cut end was pointing upwards. I used the test tube holders to put the test tube into the water bath and fill the test tube with water from the bath. 3. After checking the temperature in the test tube, I added a quarter of a lab spatula of Sodium Hydrogen Carbonate to the test tube and stirred gently. 4. Immediately after doing so, I timed for 30 seconds on my stopwatch whilst counting the number of bubbles produced from the cut stem of the elodea. I repeated this test a further two times to give me three results for this temperature. 5. I turned the temperature control on the water bath to 40�c in order to prepare for the next temperature test. 6. I repeated these steps for each temperature, lowering the temperature of the water bath to the temperature required. My Preliminary Experiment: My preliminary experiment allowed me to identify faults in my plan and alter them for the real experiment. I needed to work out which temperatures I could count the gas bubbles at, and found that at the temperature of 60�c, none were produced. ...read more.


Cloud cover could have altered the amount of light allowed to the plant, as the day passed. If so, this could not be helped. Conclusion: How does changing the temperature affect the rate of photosynthesis? To answer my original question, as the temperature increases, the rate of photosynthesis increases - more oxygen bubbles are produced. The higher temperatures allow more heat energy to be absorbed by enzymes, and collide with the carbon dioxide and hydrogen which they can only accept, they consequently work more quickly, and collide more frequently. Evaluation: I managed to conduct this experiment with as little help as possible, only allowing another person to help time with the stopwatch. I am happy and confident that my results are of a good quality and reliable. If I were to conduct this experiment again, I should like to repeat my readings more than three times to ensure I have the most reliable results possible, along with a more accurate average. My error bars are of a reasonable span. My technique throughout the experiment was good, though occassionally due to the complexity of this investigation, the elodea was left in the water longer than other times, therefore it could've become more familiar with the temperature, slowing down its reaction. Imogen Kirk 24th February 2010 ...read more.

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