Cell PHEOC

Problem: What affects will different combinations of substances have on a cell?

Hypothesis: When the cell is in a thin substance the cell membrane will grow, because the small substances will be let into the cell membrane. When the cell is in a thick substance the cell membrane will shrink, because the large substances won’t be let into the cell membrane and the water molecules will spread out.

Experiment Design:

Materials:

-Microscope

-Slide/ Slide covers

-Beakers

-Tweezers

-Pipette

-Water

-Blue Dye

-Hydrochloric Acid

-Sugar

-Salt

Variables:

CV: The onion, the slide, water, blue dye

IV: The substance around the onion.

DV: The effect of the mixture on the onion

Procedure:

We regularly took the epidermis of the onion, this was the part of the onion with only one layer so that there was no overlap. After taking the epidermis we placed it on the slide. We then took the substance we were using and dissolved it into blue dye and water in a small beaker. Once that was done we would take a pipette (eyed dropper) and squeeze the mixture onto the onion. At that point we put on the slide cover and looked into the microscope. We finished by writing down our conclusion on each substance.

                                                                                                                                                                       

Observations:

After looking at the first substance we realized we could see the nucleus in each cell. Sometimes we could not see the nucleus because there was not enough blue dye. We also concluded that salt was thin enough to come into the cell; this process is called Osmosis. The same thing happened to the sugar. When we tested hydrochloric acid we concluded that the cell is a hypertonic solution because the cell shrunk.

Conclusion/ Analysis:

Callie and I wanted to see what would happen to a cell when put in different substances. We predicted that the salt and sugar molecules would be able to move freely in and out of the membrane because of their small size. In our research we discovered that the cell lost water and shape due to the action of diffusion. When doing the experiment we were confused because sometimes we could see the nucleus and sometimes we could not. After discussing with Mr. Roehl we realized we simply did not have enough blue-dye in some of the mixtures. Even though many of our variables changed and our experiment did not bring one result, we still found things we expected to see.