Photosynthesis Lab Report

Introduction
Photosynthesis is a redox reaction which requires carbon dioxide, water and light to produce water and a 6-carbon sugar. The process of photosynthesis consists of two parts, a light reaction and a light-independent reaction. The method of changing light energy into chemical energy for the formation of NADPH and ATP is done through the light reactions. Light independent reactions use carbon dioxide and the products of light reactions (ATP and NADPH) to form compounds such as glucose. The rate of photosynthesis can be determined indirect by the indicator DCPIP. When reduced this indicator changes from blue to a colorless solution. When light is absorbed, water is oxidized and the excited electrons are transferred for the process
Varied light intensities can alter the photosynthetic capability of chloroplasts. As light intensity increases, it is apparent that the rate of photosynthesis begins to decrease until a certain level of light saturation. If the intensity extends over a certain tolerance level, photo inhibition occurs. The light used for photosynthesis requires a specific wavelength for the pigments in chloroplast to absorb it. Light independent reactions occur in the stoma of the chloroplast whereas the light reactions occur in chloroplasts that sit on the thylakoid membrane. White light is comprised of all the colors in the spectrum where each of these colors contains different energy; hence they are all of different wavelengths. Since pigments only absorb certain wavelengths within the visible spectrum, the others are transmitted or reflected. Blue and red light tend to contribute to the highest rates of photosynthesis whereas green and yellow result in the lowest rates. The purpose of the experiment was to investigate photosynthetic electron transport, using isolated chloroplast from silver beet leaves. Red light tend to contribute to the highest rates of photosynthesis whereas green result in
Measure the light intensity in each box so that you can correct (normalize) for the different intensity by dividing the measured rate by the intensity. This gives a rate per foot-candle and allows you to compare the effectiveness of the light based on color alone. In tube 2, there is a decrease in the absorption rate when the reaction mix is mixed. In test tube 3, the readings of the absorption rate decreases when in the presence of light. There is a decrease in reading up till the 60th minute and then the absorbance rate decreases in test tube 4. In test tube 5, there is a decrease in absorption rate when DCMU is mixed. The readings for the absorption rate increases up till the 30th minute then it would decrease in test tube 6. In test tube 7, the readings increase up till the 30th minute then it would decrease and increase