Photosynthesis: Examining Photosynthesis And Cellular Respiration

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Examining Photosynthesis and Cellular Respiration
Introduction- In Lab 4, the purpose was to examine the process of photosynthesis and cellular respiration and understand the correlation between these two processes (BIO 202, Lab 4, 2016). Photosynthesis is a process used by plants and other organisms to convert solar energy into chemical energy; which is then used to fuel the organism. The equation for photosynthesis is 6CO2 + 6H20 + Solar energy ---> C6H12O6 + 6O2. This process has two subparts, light reactions and calvin cycle. The light reactions in photosynthesis is driven by light and cannot occur unless light is present. The calvin cycle is light independent and functions in the dark. Cellular respiration is a set of metabolic reactions
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In cellular respiration glucose molecules are broken down through these reactions in order to produce ATP. The equation for cellular respiration is as followed: 6O2 + C6H12O6 ---> 6CO2 + 6H2O + energy. The hypothesis was, while CO2 is being given off during respiration, it can be re-utilized during photosynthesis. For this experiment the thought was, if a sealed test tube containing CO2, bromthymol blue, and an elodea plant in an environment with light, it will result in a color change from yellow to greenish blue. Also, if a sealed test tube containing bromthymol blue and an elodea plant in a dark environment. The bromothymol blue, a pH indicator, was used to measure the amount of CO2 present in a given test tube. The controls being tested were two negative controls that consisted of one test tube containing bromothymol blue, CO2, and an elodea plant while being in a dark environment. The second negative control consisted of a test tube containing …show more content…
It is predicted that the elodea plant would undergo photosynthesis and cellular respiration in its given environment. For this reason, it is also expected that the color of bromthymol blue will change colors throughout the duration of this experiment due to changes in the CO2 level in a sealed test tube. The results do support the hypothesis. The results show significant differences in color change in its respective environment. After performing the experiment with several samples in each environment, the results support the hypothesis that during photosynthesis CO2 will be re-utilized, and during cellular respiration CO2 will be given off. The color change in the light showed complete uptake of CO2, this can be concluded because the absence of CO2 changes the beginning color (yellow) to the ending color (blue). However, the color change in the dark showed appropriate production of CO2, this can be concluded because the presence of CO2 created a green/yellow color from the original color (blue). An alternative hypothesis to further evaluate the production of CO2 during cellular respiration would be, if the experiment had a longer duration of time, the dark reactions would produce more CO2 through cellular respiration causing the color of bromthymol blue to turn yellow. The negative control in the light environment containing bromthymol blue and

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