Purpose: The purpose of this experiment was to see the impact NH4Cl has on tetrahymena. The independent variable for this experiment was NH4Cl. Dependent variable was the impact NH4Cl has on tetrahymena population. Control was the tetrahymena solution without NH4Cl. In total, there should be 27 replicates per group, 9 per person.

Procedure:

1. Pipette 450uL of PPT in 3 different wells.
2. Pipette 50uL of tetrahymena into the 450uL of PPT in well 1.
3. Place lid over plate and shake.
4. Transfer 50uL of well 1’s solution into well 2. Shake.
5. Transfer 50uL of well 2’s solution into well 3. Shake.
6. Add 10uL of iodine to each well.
7. Observe the tetrahymena under microscope, choose the dilution that will give you 10-30 cells in a 10uL drop.
8. Dilute culture to 1000 cells/ml so there is enough for everyone in the group. 6mL per student.
9. Determine class average by using C1V1=C2V2. Our class average was 247.
10. Make dilution in a 50mL tube. Add 247uL of tetrahymena, then add PPT to the 20mL graduation mark. Mix.
11. Add to 750uL of the solution made in step 10 to six wells.
12. Add 250uL of NH4Cl to 3 of the well. This is the dependent variable.
13. In the other three wells, add 250uL of DI water. This is the control.
14. The next day, come back to lab to count tetrahymena in each solution.

Data:

Conclusion: Overall, this experiment further helped me with serial dilutions and micropipetting. Also, this experiment taught me how to do calculations such as C1V1=C2V2. This also helped me understand about how much tetrahymena lives in soil that has used fertilizer with NH4Cl.