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Photosynthesis.Prediction: As I increase the amount of heat being applied to the elodea the rate of photosynthesis will rise at a directly proportional rate.

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Biology Coursework - Photosynthesis Prediction: As I increase the amount of heat being applied to the elodea the rate of photosynthesis will rise at a directly proportional rate. As the temperature reaches 40* the rate of photosynthesis will start to decrease. As the temperature increases, the rate of photosynthesis will continue to fall, starting to fall quite slowly, but the decrease will speed up until reaching 0 at roughly 60*. Elodea are autotrophs, these are organisms, which use chlorophyll to make energy needed for food by photosynthesis. Like all autotrophs, certain ingredients are needed for the photosynthesis to occur, for the maximum photosynthesis rate, a never ending supply of all the key ingredients is needed, if there are few of one or all of the ingredients then photosynthesis will be limited. As such, the lack of 1 ingredient can limit the entire rate of photosynthesis. The main factors in a plants rate of photosynthesis are: 1. Day Length (Photo period) 2. Light Intensity (strength) 3. Light Wavelength 4. Temperature 5. Carbon Dioxide Availability 6. Water Availability Each of these ingredient's are needed in photosynthesis for different reasons, but without a combination of them all, photosynthesis cannot take place. Inside the chloroplasts, the carbon dioxide and the light are used by the chlorophyll and glucose and oxygen are given out, the glucose is used for energy by the plant and the oxygen is given off into the atmosphere as a by product of the reaction. The enzymes inside the chlorophyll work best at their 'optimum' temperature, so hence heat is a factor, as if the plant is too cold the plant will not photosynthesis as quick ...read more.


Safety: Because we are heating water we must wear eye goggles, we must not touch hot glass and we must tuck in out ties, long hair and any loose clothing etc. Results: After repeating the experiment 3 times I drew these results: The Table and Graphs of my results agree with my prediction. As the heat is increased the rate of photosynthesis increases at a directly proportional rate until roughly 30', here the rate of photosynthesis slows down, at 40' it stops increases and starts decreasing, it decreases rapidly until roughly 60', after which there is no photosynthesis This can all be explained, as the heat is increased, the rate of photosynthesis rises. This is because the enzymes in the chlorophyll are being heated up and are working quicker and quicker, the more heat they have, the quicker they will work, hence the higher rate of photosynthesis, until 35' -40' where they reach their optimum, this is shown in the graphs by the straightening off of the graph between 30' and 40'. The severe drop in the rate of photosynthesis, back to 0 after 40' can be explained too. The plant has reached it's 'optimum' temperature for photosynthesis, after this point the cells become denatured, they stop working and photosynthesis stops, this is why the rate of photosynthesis drops rapidly after 40' because all the chlorophyll have been denatured. These results support my prediction. The graph is very similar to my graph prediction. Both graphs rise at a directly proportional rate until 35', where they both level off. ...read more.


I believe I can be very confident in my results. The revised method got rid of most of the problems with the original method and the fact that every time I repeated the experiment without forgetting something the results were very similar. There are clear patterns throughout all 3 useful results that are echoed in the average. I believe that the difference between the ending (after 40') of my prediction graph and the actual graph can be explained. As the plant got heated the oxygen trapped inside the plant would have expanded, at 40' plus, it expanded to the point where it was being pushed out of the plant, and appeared like the plant was still photosynthesising, this explains why it takes longer for the rate of bubbles per minute to drop in the actual experiment. If I was to repeat the experiment this could begot rid of by only measuring the amount of oxygen being produced and not measuring all the gasses coming out of the plant. There is more we could do to these results. To improve them we could repeat the amount of times we repeated the experiment to get a more accurate average. We could collect data on the effect of the other factors of photosynthesis, maybe repeating the experiment but rather than having heat as the independent variables we could have, day length, light intensity, light wavelength, carbon dioxide availability and water availability in turn as the independent variable. This would give us more ideas into the levels the control variables could be kept to help our experiment. By doing this we could gave all the control variables at their 'optimum' point and thus the experiment would work as well as it possibly could. ...read more.

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