Membrane Function Lab Planning – Hour 4, Group 5

Consider the following questions to help you get started:

  • What variable will you be testing (independent variable)?
  • What variable(s) will you be measuring (dependent variable)?
  • What variables will you hold constant (constant variable)?
  • What evidence would confirm that the stain has crossed the membrane?
  • How will you be confident in the validity of your results?
  • What will you use as a standard of comparison (control group)?

Use the comment form below to discuss the plan for your experiment.

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6 Responses to Membrane Function Lab Planning – Hour 4, Group 5

  1. William S. says:

    If we put a small amount of dye on the yeast, then the yeast will become red. However, overtime, the yeast will turn back to its regular shade of gray. If the yeast first turns red and then turns back to gray after a few minutes, then we will know that our hypothesis(the stain enters the cell and then is transported out) is correct. We will also have a cup of yeast solution as our control to insure that something like the temperature of the room isn’t effecting the color change. The experiment will be performed multiple times(like two or three) so that we know our results are accurate. We will need a small amount of yeast solution and Congo red. Please comment if you have any questions or comments, as well as other experiment ideas.

  2. Mia D says:

    That all sounds good. The independent variable will be the dye we put on some of the yeast. The dependent variable will be what color the yeast is after a few minutes. From the background information, we know that it should be gray or red. The constant will be the cup of yeast solution that William mentioned. The evidence that will confirm that the stain has crossed the membrane is if the solution turns back to gray or not. As William stated above, we will perform this experiment multiple times to confirm the validity. Also, we will need a small amount of yeast solution and Conga red.

  3. Logan C says:

    Yes, I agree. The independent variable should be the dye we put on the yeast, and the dependent variable will be what color the yeast is after waiting a few minutes. The constant should be the cup, and the temperature of the room so that it won’t affect our experiment. Again, we will need a small amount of yeast and Congo red.

  4. Ella M. says:

    That all sounds great. We should also record the amount of time it takes for the yeast to turn back grey, that way we can see if there was an outlier in our results, which will help us to correct our process. Also, I agree that we should preform the experiment multiple times to get the greatest amount of accuracy. William is right, other factors could be contributing to the color change, so both a constant and multiple tests will help us get accurate data.

  5. Mia D and William S says:

    Place one drop of unboiled yeast solution on two different slides; place one slide aside. Add one drop of Congo red on the remaining slide. Wait 3 minutes. Place the slide with the dye under the microscope. Record color of the cells. Place the controlled slide under the microscope; record the color. Repeat steps 1-6 for the boiled yeast cells. Record your results and draw a conclusion. Share your results.

  6. Ella M. and Logan C. says:

    We conclude that the non-boiled yeast cells remove the Congo red dye through active transport, while the boiled cells do not remove the dye because they cannot complete active transport. We conclude this based on our results which read that the boiled yeast cells stayed a reddish tint through the time studied, while the non-boiled yeast cells slowly turned back into a cream/grey color. The non-boiled yeast cells are alive and healthy, allowing them to remove the dye through active transport, and therefore turn back into a cream/grey color. The boiled, however, were not healthy, and therefore could not provide the energy to complete active transport and remove the dye. This stopped the boiled cells from turning back into their original color. Some areas of possible error include: Not having precise measurements of the drops of yeast and the drops of dye, and a slight change of temperature in the room which could have affected the cells.

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