Elodea Experiment

1277 Words6 Pages
A total of two different exercises were preformed in the present experiment. A simulation of an undersea plant, Elodea in this experiment, was utilized to observe how strands of the plant respire in certain conditions. Four clean test tubes were obtained and filled to the brim with bromothymol blue (BTB); a neutral base with a pH of 7.0. Two tubes, one with an elodea strain, the other with just the BTB, were exposed to a bright light shining on them. The remaining two test tubes, one with another elodea strain, the other with just the BTB, were shielded from the light and were considered to be in the dark. The color and pH of the tubes (7.0 for all tubes) was noted pre-exposure and then post-exposure (sixty minutes in light or dark). The color…show more content…
There are two types of photosynthetic processes: oxygenic photosynthesis and anoxygenic photosynthesis. Oxygenic photosynthesis is the most common and is seen in plants, algae and cyanobacteria. During oxygenic photosynthesis, light energy transfers electrons from water (H2O) to carbon dioxide (CO2), which produces carbohydrates. In this transfer, the CO2 is "reduced," or receives electrons, and the water becomes "oxidized," or loses electrons. Ultimately, oxygen is produced, than released, along with carbohydrates used for food. Photosynthesis is, in a nutshell, a chemical process through which plants, some bacteria and algae, produce glucose and oxygen from carbon dioxide and water, using only light as a source of energy. In this experiment, we saw that even underwater plants (Elodea) respire, by exchanging carbon dioxide with the water, in the form of Carbonic Acid. When CO2 is used in photosynthesis, the level of Carbonic Acid drops. Thus, water living organisms have the ability to change the pH of their environment as they add or remove CO2. Bromothymol Blue was added to the test tubes as a neutral pH of 7.0. Less light, less photosynthetic reaction and vice versa. An equation that summarizes photosynthesis is: 6CO2 + 6H2O +light & chlorophyll ------> C6H12O6 + 6O2 and when in water, carbon dioxide dissolves to from…show more content…
A stronger presence of blue was noted at the end of one hour in tube two, with the Elodea, indicating that photosynthesis did occur rapidly. The two tubes in the dark changed to a yellow color, indicating a lower pH. Findings for experiment two did not support our hypothesis that temperature influenced bubble length, yet it appeared the type of substrate had a more direct impact on bubble length. Glucose and Fructose had the largest difference in bubble length from start to finish; all finings are shown in the tables and graphs

More about Elodea Experiment

Open Document