Membrane Function Lab Planning – Hour 4, Group 7

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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7 Responses to Membrane Function Lab Planning – Hour 4, Group 7

  1. Ian G says:

    The independent variable that we are testing would probably be the congo red because we are trying to see if it will pass through the plasma membrane. We will know the stain has crossed the membrane when we see the red dye inside of the yeast cell. Our control group will be testing it multiple times.

  2. Ian G says:

    To test the hypothesis we could put the red dye in the yeast and if the yeast turns red, then back to it’s normal color in a couple of minutes we will know the hypothesis is correct.

  3. Danny R says:

    The dependent variable in this test we are doing, I think, will be the yeast. I think this because the yeast is the variable that the Congo Red will, the independent, will be effecting. If the experiment works then the yeast will get a red color from the Congo Red.

  4. Danny R says:

    To get the validity of our tests what we would need to do is to test the same experiment multiple times and get the same result. If this would happen we would know that our tests were successful.

  5. Campbell N. says:

    I agree with Danny, we would definently need to do it at least twice before finalizing our results. If our hypothesis is that it changes color, then to be correct, the yeast would need to change color.

  6. Ian G, Danny R says:

    Conclusion: The hypothesis, the stain moves into the yeast cells through passive transport and moves out of the yeast cells through active transport, is correct. This is proven by observing the alive yeast performing active transport and pushing the stain out of the cell. The boiled yeast could not push the red out because it was dead. Possible sources of error are, miscounting the amount of cells with red in them, having different amounts of light on the cells, or not putting the same amount of Congo red stain on the slide.

  7. Campbell N. says:


    For our procedure, we first took a slide and a dropper to the yeast. We picked up the yeast with the dropper and drooped on drop on the slide. After that, we then took one drop of the red dye with a different dropper, and squeezed one drop on top of the yeast. Then we took a tooth pick and mixed those two substances around until they were dissolved in each other. After that we put the cover slip on. We waited three minutes to soak up the remaining dye with a paper towel. Finally, we observed our observations.

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