Anas Ahmed 10JCBiology Controlled Assessment- Investigating the rate of photosynthesisAll living things require energy to carry out their life processes. The green plants obtain their energy from sunlight for their life processes. They capture the solar energy and then convert it into a chemical energy. Photosynthesis is an important process , to plants, because they produce glucose and they use the glucose to produce other important and useful chemicals such as fats, proteins and vitamins. The oxygen released as a by-product, vital to respiration in plants and animals. Therefore, photosynthesis can be considered the ultimate source of energy for life and for nearly all plants and animals ...view middle of the document...
Photosynthesis is a chemical reaction, and enzymes act as catalysts to speed up the reaction. Enzymes work best at an optimum temperature (370C). At low temperatures, the enzymes, become less active and at high temperatures they become denatured. This indicates that the factor temperature will have an effect on the rate of photosynthesis.Light will also have an effect on the rate of photosynthesis as light is the energy source for the chemical reactions. Higher the intensity of light will provide the plant with more light energy, whereas lower the intensity of light, there will be a lower quantity of light energy available. The intensity of light will also affect the rate of photosynthesis.The third factor is Carbon Dioxide, this is a reactant in photosynthesis. The quantity of Carbon Dioxide will affect the rate of photosynthesis. Higher the quantity of Carbon Dioxide will increase the rate of photosynthesis when the availability is less the rate of photosynthesis will slow down.Photosynthesis being a chemical reactions depends on more than two factors. The factor which is the least amount in this reaction will limit the rate of photosynthesis, this is known as the limiting factor.To find out the rate of photosynthesis we did a set of preliminary trials. These trials that we carried out was to find out the effect of light, carbon dioxide levels and temperature on the rate of photosynthesis. The main purpose was to, also see if any practical difficulties that we may encounter. Thus we can modify the final experiment to overcome any practical difficulties.The diagrams below shows the setup of the apparatus in our trials, to find out the effect of temperature, Carbon Dioxide and light.The rate of photosynthesis was measured by counting the number of oxygen bubbles released per minute inside the test tube.In the first week of preliminary trials, we carried out the effect of water temperature on photosynthesis. The method is as follows: We had five different water baths, all the water baths had five different temperatures, these temperatures were, 10C, 100C, 220C, 370C & 450C. We collected the Elodea pondweed and submerged it with the different water temperatures and collected the oxygen bubbles shown in the diagram. At each temperature we left the pondweed for five minutes and counted the amount of bubbles produced each minute.During the preliminary trials, we discovered that at low temperatures such as 10C and 10 0C. The oxygen bubbles released were either too slow & low in quantity. At room temperature (220C)the bubbles released by the pondweed were also insufficient, furthermore at the higher temperatures such as 370C the bubbles were producing at rapid pace, making it very difficult in counting the oxygen bubbles. Finally at 450C the oxygen bubbles did not produce as within the five minutes nothing was released by the Elodea pondweed.The next factor in our investigation was the effect of carbon dioxide. The method in which we carr...
