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Lab Partners: Rachel Payne, Teddy Ofosu , and John Vlahos
Biology Lab 10100
02 April 2017
Professor Yadesh Ramdihal
The Effects of Potassium Chloride on the Motility of Paramecium Tetraurelia Cells
Paramecium tetraurelia is a unicellular organism from the kingdom Protista. These cells can be cultures in laboratories easily because it poses no ethical or health concerns. The cilia on the paramecium allows the cell to move so it can find food, interact, and avoid predators. Prior to this experiment, there was paramecium's behavior and swimming speed in different environments previously observed. Potassium chloride is a metallic water-soluble salt that benefits the medical field. KCl in small dosages can help those with low levels of blood potassium. When used in high dosages, KCL is typically found in the lethal injections, because the high dosages would lead the heart to cardiac arrest. When the paramecium were placed in an environment with the salt, potassium chloride, the organisms swam slower with the solution. Thus gathering the salt affects the organism's behavior. Prior to experiments, there were discussions about other types of chlorides and their effects on the Paramecium culture. When focusing on CaCl calcium chloride, there was a hypothesis that when 5 drops of the substance was added to the culture, the paramecium swimming would decrease in motility. 3 drops of NaCl sodium chloride would decrease the swimming speed of the culture because paramecium usually reside in freshwater, adding salt to the culture would create a saltwater environment, decreasing their speed. (Course Supplement 6-8)
Through the usage of earlier experiments and visual observations, there was a general understanding that there is a correlation between paramecium motility and potassium chloride. It became evident after the 2 drops of potassium chloride was applied the solution where the paramecium culture swam, and this lead to an alteration in their swimming behavior. But this is only an observed correlation, in order to to legitimize this statement, we created an experiment in hopes to prove the hypothesis when potassium chloride is present in the solution where the paramecium culture swim, there will be an decrease in motility, correct. The null hypothesis is the potassium chloride will not decrease the motility of the paramecium .
In this experiment, the independent variable is the potassium chloride concentration , and the dependent variable is the swimming speed of the paramecium in millimeters per second )mm /s). Standardized variables include; the paramecium (derived from the same culture), temperature of the environment, and lighting. There were two levels of treatment, experimental and control. The experimental treatment levels included the group of paramecium that was cultured with two drops of potassium chloride. The control treatment was the group with only paramecia, and not any KCl . There were five replications of this experiment, including five sample sizes per treatment level. The species used in the experiment were Paramecium tetraurelia .
The experiment was executed with the following method. A transfer pipette was used to place a drop of the paramecium culture into 2 different weight boats. The paramecium was then placed under the compound microscope, and using the lowest magnification, found the cells swimming in the culture, and observed the swimming behavior of the organisms. The culture was placed on depression slides. The motility was recorded through the use of a millimeter grid and a timer, after one minute, allowing the culture to adjust to the KCl concentration. The control treatment group was observed separately.
The experimental prediction for the experimental treatment group, which is the group of paramecia that had added KCl concentration to its culture, these paramecia would decrease in speed significantly in comparison to the control treatment group, the group of paramecia without added KCl to their concentration. This data has been analyzed through the use of descriptive statistics.
Results and Data Analysis
The graph below depicts the difference in motility between the experimental treatment group and the control treatment group. The mean (average speed) of the experimental group was found to be 0.158108mm/s with a standard deviation of 0.173226mm/s. While the mean of the control group was found to be 0.54836mm/s with a standard deviation of 0.28743mm/s. The standard deviation is represented
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