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Introduction

12.12.11 Aleksandra Katarzyna Rosiczka I High School im. Stanislawa Staszica w Lublinie Lab report no.1 Elodea Lab-Photosynthesis Candidate's number 002094- 023 Aleksandra Katarzyna Rosiczka ________________________________________________________________ TITLE Determine the affects of light intensity on the rate of photosynthesis in plants- research based on process of photosynthesis in elodea. BACKGROUND Photosynthesis is the process by which plants, some bacteria, and some protistans use the energy from sunlight to produce sugar (glucose), which cellular respiration converts into ATP, the "fuel" used by all living things. The conversion of unusable sunlight energy into usable chemical energy, is associated with the actions of the green pigment chlorophyll. Most of the time, the photosynthetic process uses water and releases the oxygen that organisms absolutely must have to stay alive.1 The equation of photosynthesis: 6 H2O + 6 CO2 + energy C6H12O6 + 6 O2 Photosynthesis uses only light energy and simple inorganic substances, and involves many stages controlled by enzymes. Since photosynthesis is a light dependent reaction, the intensity of light should affect the rate of photosynthesis. As one of the products of photosynthesis is oxygen, therefore the oxygen concentration will be measured to show the effects of photosynthesis. The process of photosynthesis is undoubtedly affected by light intensity. At low to medium light intensities the rate of photosynthesis is directly proportional to light intensity. ...read more.

Middle

All members of the group should have the same information in their notes. Candidate's number 002094- 023 Aleksandra Katarzyna Rosiczka ________________________________________________________________ DATA COLLECTION & PROCESSING Number of the test tube 1 2 3 4 Time(min.+/-1s.) Number of trials 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 Number of the oxygen bubbles (+/- 1 bubble) 10 3 2 3 3 0 0 0 0 4 3 3 4 0 0 0 0 20 17 15 16 15 0 0 0 0 20 21 21 21 0 0 0 0 30 44 40 40 43 0 0 0 0 56 54 43 53 0 0 0 0 Figure 1. Amount of oxygen production 1-Elodea, sodium bicarbonate water, light energy 2-Elodea, aerated water, lack of light energy 3-Elodea, sodium bicarbonate water, light energy 4-Elodea, aerated water, lack of light energy Figure 2. Measuring of the oxygen production during the process of photosynthesis Candidate's number 002094- 023 Aleksandra Katarzyna Rosiczka ________________________________________________________________ Range of the oxygen production in elodea 1st tube Max. value 44 Min. value 3 2nd tube Max. value 0 Min. value 0 Rate of the photosynthesis= number of oxygen bubbles/ time Rate of photosynthesis after 10 min. 1st tube: 0.3 ; 0.2; 0.3; 0.3 2nd tube: 0 3rd tube: 0.4; 0.3; 0.3; 0.4 4th tube: 0 Rate of photosynthesis after 20 min. ...read more.

Conclusion

If had not been added, the process of photosynthesis would not have occurred because the distilled water does not have CO2 which is needed for this process. This experiment was based on the light from 160W bulb. Although the experiment resulted successfully there are several problems that appeared along the work that could certainly be improved so that the results become more accurate. Some errors and solutions to them are presented on the table on next page. Candidate's number 002094- 023 Aleksandra Katarzyna Rosiczka ________________________________________________________________ ERRORS SOLUTION > Energy was from artificial light. The results can be different if it would be used another energy from the sun. > Another substances which have been in the tubes after previous experiments. The tubes should be cleaned more carefully before using second time. > The weight checked by an electronic balance wasn't exact. Try and be precise as possible to be exact with measurements. > Sometimes the air bubbles released from elodea did not go straight to funnel and were on the leaves until bigger bubbles collected, hence those smaller bubbles volume was not recorded at a time it had to be. Try to be more carefully to count bubbles. Figure 7. Errors and solutions to them But besides of the observations made and the errors made, the work was finished and obtained data was relevant and reasonable to determine the affects of light intensity on the rate of photosynthesis in plants- research based on process of photosynthesis in elodea. ...read more.

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