Objective:

The goal of this lab was to practice running our experiment about the effects microplastics has on Tetrahymena with a control and treatment group. While the lab also allowed our group to practice calculating cell count and observing behavioral assays that will be used in our future experiments. Another important objective for this lab was understanding spectrophotometers and how their data can contribute to our experiment.

Purpose:

The purpose for this lab was mainly to prepare us for our future experiment on how do microplastics affect Tetrahymena. This lab served as a beneficial practice in order for our group to properly and efficiently carryout our own individual lab.

Procedure: 

Sampling

•  Divide into pairs with another student that preformed the same behavioral assay in the previous lab.
• Transfer 4ml of the treatment and control into separate sterile glass test tubes using a serological pipette.
• Use a spectrophotometer to measure the optical density of the control, treatment, PPT media, and the PP.

Cell Count

• Add Three drops 2µl of the control and treatment Tetrahymena onto separate slides with a pipette.
• Add one 1µl of Iodine to each of the six 2µl drops.
• Observe one slide at time and use a phone to take a picture of the cell count for each of the three drops.
• Repeat this procedure for the second slide in order to have six photos, three for the control group and another three for the treatment group.
• Analyze the photo and determine the cell count for each of the six drops, record the data into your lab notebook.
• Calculate the average cell count per ml for the treatment and control group.
  • Use the equation (average of cell/3)x Dilution factor (1.5) x (1000µl/ml) = average cells per ml.

Behavioral Assays 

• Use a pipette to take 20µl of the control and treatment group and separate drop both samples of 20µl onto separate slides.
• Take one slide and place it onto the stage of the compound microscope that is connected to the large display screen.
• Adjust the stage of the microscope to make sure the image is clear and the cells are visible.
• Once the cells are visible, use a phone to record the screen that displays the moving cells.
• Record a video for two minutes and after every thirty second interval, adjust the slide in order to observe a new group of cells.
• Repeat these previous steps for the other slide that was prepared, the other experimental group.
•  Analyze the video and chose one cell to focus on for ten seconds, use a phone as a timer. During the ten seconds count the number of direction changes  the cell preforms and the amount of seconds the cell is spinning.
• Repeat the previous step ten times to gather ten trials of different cells.
• Record the data in your lab notebook and calculate the average direction changes and the average seconds the cell is spinning.

Data and Observations:

Optical Density data

Cell count data

Control average cell count per ml: 6333.3

Treatment average cell count per ml: 49833

Directional Assay

Observations:

Control group

Drop 1

Drop 2

drop 3

Treatment

Drop 1

Drop 2

Drop 3

Storage:

After using the serological pipette it was placed in its proper location for future groups to use and the micropipettes were placed on their rack and the tips were disposed. The slides were cleaned appropriately by rinsing them with water and were dried by using paper towels. The compound microscope was unplugged and covered with its correct sheet.

Conclusion 

The lab was very beneficial for group because we were able to have a sense of how our experimental procedure and possibly results will be. The data recorded in this lab display more cells in the treatment group and  the average direction change/seconds spinning were less than the control group. This data leads to suggest that the addition of the twine juice had an effect on the Tetrahymena. These findings are not a hundred percent accurate but can only support the hypothesis that twine juice does affect Tetrahymena. Lab 7 greatly prepared us for our future group experiment and has increased our skill of calculating the cell count and studying behavioral assays because were are more familiar with the procedure. Overall this lab was very important for our group and very important to increase our lab skills.

Future steps:

The main future step our group has is expanding on this lab by preforming numerous trials and have our own variables that we will manipulate. Our group understands the basic procedures and now only need to focus on what we will be manipulating. I feel that my group is ready to begin our experiment and excited to start a new lab that is based on our knowledge and procedural skills.