Sarah Alsilwi
Diana Cardenas, Emely Dominguez

The Effect of Potassium Chloride on the Swimming Speed of Paramecium Tetraruelia


Paramecium tetraurelia is a unicellular organism from the kingdom Protista, that can digest food and reproduce. Paramecia can move in all directions because of the hair-like protrusions on the surface of the cell (CCNY Lab Manual, p. 7). Some initial observations that the class groups presented were that the Paramecium tetraurelia swam at quick velocity and spiral movement. Another observation was that the Paramecium swam at a faster rate when Calcium Chloride was added. Moreover, class groups discussed the importance of Potassium Chloride in that it leads to muscle weakness and even cardiac arrest. Potassium Chloride otherwise known as KCL, is a chemical compound that is classified as a salt because its ions have opposite charges. KCL is a common substance used in plant fertilizer, medication or even a fire extinguishing system. According to Effects Of Potassium Chloride On Your Heart by Z Living Staff (2017), KCL regulates the heartbeat, slowing it down for people with high blood pressure. In other words, adding too much potassium to the body, limits the amount of potassium that can be pumped into a cell, causing the pump to be deficient, leading to the heart not having the right amount of energy it needs to beat. KCL causes heart rate deceleration which incited the hypothesis since cells in the body use too much of their ATP to simply push in potassium ions, which lessens the amount of ATP that would help the cell move faster. If this occurs in human body cells because the energy used to enter potassium into the cell causes the cell to lose energy for its movement, then the Paramecia might also be effected similarly when Potassium Chloride is added due to the K+ ions.
Therefore, it was hypothesized that the addition of Potassium Chloride to Paramecium solution would slow down its ciliary movement, decreasing the velocity of the paramecium. The null hypothesis was that the addition of Potassium Chloride would not display any sort of difference in the movement of the cilia, posing no difference in the velocity of the Paramecium.

Experimental Design:
The independent variable for this experiment was the Potassium Chloride (KCL), while the dependent variable was the ciliary movement or swimming speed of the paramecium. The standardized variables were the culture and number of paramecium, the number of drops of KCL, the slides the paramecium were placed in, the microscope and the temperature of the lab room. The treatment levels consisted of two treatment groups, the controlled group and experimental group along with two drops of Potassium Chloride. The replication being 25 times in which the experiment was carried out for both groups. The sample size was 25 paramecia observed per treatment level and the species is Paramecium Tetraurelia.
In both treatment levels, 3 drops of paramecium solution (using a pipette) were placed on a microscope slide and covered with a cover slip. The depression slides had millimeter grids beneath them (to record the velocity of the organism) and were all placed under the compound microscope. The movement of the paramecium was tested by the number of millimeters the P. tetraurelia traveled through in sixty seconds. One member used a stop watch to manage the time and another member observed through the microscope, counting the number of boxes (or millimeters) a paramecium swam through until the minute was over. These steps were carried out in the control group, in which paramecium solution contained no addition of KCL in the depression slide (that was held down by stage clips). The number of boxes that the organism travelled through on a grid were counted for the control group 25 times. The experimental group was tested using the same steps in which 3 drops of paramecium solution was placed on a depression slide, however this time with the addition of two drops of KCL. This was carried out 25 times, using the same steps to record the velocity with a millimeter grid under the slide and on the compound microscope. The comparison of data between the control and experimental group would help conclude whether the paramecium traveled faster or slower.
The class predicted that if