Photosynthesis Lab Report
This process occurs in the chloroplasts (Ashraf & Harris, 2013). Cellular respiration, conversely, occurs in the bacteria’s cytoplasm an in eukaryotic mitochondria, where energy is produced as a result of the glucose breakdown to yield energy in form of ATP molecules. The aim of the experiment is to investigate the sunlight effects on photosynthesis rate and to prove that sunlight is required for photosynthesis. Light conditions effects will be assessed on leaf discs for photosynthesis, and in the dark condition, cellular respirations will be assessed. The hypothesis of this experiment is that increased exposure of the leaf discs to light promotes photosynthesis, and reducing light intensity leads to slower photosynthesis rate. As oxygen is being produced, the leaves float because they become lighter.
Additionally, different lights were used to assess the photosynthesis rate. In this case, red, green, and blue lights were used. A few leaves in the bicarbonate solution were exposed to red light first, then observations were made on whether they responded by floating. Some other leaves were exposed to green light, then observations made. In this experiment, the hypothesis that light conditions affect photosynthesis rate, and dark condition promote cellular respirations, and that increased exposure of the leaf discs to light promotes photosynthesis, and reducing light intensity leads to slower photosynthesis rate was proved to be true. It was expected that the leaf discs would float when exposed to light source in presence of bicarbonate and water because photosynthesis would take place.
Bicarbonate solution was used as carbon dioxide source. Photosynthesis used the carbon dioxide and light in presence of water to form glucose and oxygen. The oxygen was lounged in the leaf discs stomata and other structures, leading to reduced weight of the leaf discs, resulting in floating of the discs. Green light showed the least photosynthesis rate. Therefore, white light promotes faster photosynthesis that red, blue and green lights. In the second experiment, the light intensity effect was investigated. The photosynthesis rate was measured as ET50 at different light intensities. During the experiment, light source was taken further from the leaf discs and the floating rate measured. During this time the oxygen that was produced during photosynthesis that made the leaves to float was used in generating energy as ATP, and therefore, the leaves started sinking.
According to the experiment, as time passed the rate of sinking of the leaves increased. When time was zero, four leaf discs were floating. As time elapsed, the number of floating leaf discs reduced to zero when 4 minutes had elapsed. This was consent with other research studies that explain that cellular respiration in green plans occur in darkness when light is unavailable, and oxygen is being used in this process (Hunt, 2003). , & Harris, P. J. C. Photosynthesis under stressful environments: An overview. Photosynthetica. , Goto, F. , Hahida, S. , & Yoshihara, T. Effect of green light wavelength and intensity on photomorphogenesis and photosynthesis in Lactuca sativa. Environmental and Experimental Botany. Photosynthetic, respiratory and extracellular electron transport pathways in cyanobacteria. Biochimica et Biophysica Acta - Bioenergetics.
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