Cell Membrane Permeability Lab

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Introduction The cell membrane is considered selectively permeable because it chooses the molecules that enter the cell. Molecules that can pass through the cell membrane are usually small non polar or hydrophobic. It is important that the cell membrane remains selective permeable because it doesn’t want to let any molecules that are bad for the cell enter the cell. An indicator is a substance than changes color when placed in the substance that it indicates. In this experiment, iodine is being used as an indicator for starch. The purpose of this experiment is to show small nutrients that the cell needs to pass through the cell membrane. In this experiment, if the bag were permeable to starch, the starch would move out of the bag. If the bag …show more content…
The iodine is being used to determine which molecule diffuses through the bag. If the bag allows materials, then the bag could be either selective permeable or permeable. Iodine is being used as an indicator in this experiment. In order to determine if the bag allows materials through it, it is required to observe the change of color of the substance inside of the bag. This will be measured by observing the color of the substance inside of the cell before placed in the beaker of iodine and after placed in the beaker of iodine. The experiment asked to place 60 mL of water with 40 mL of cornstarch in a bag, and then fill a beaker halfway with water and then add 10 drops of iodine. The next step would be putting the bag in the beaker and waiting 15 minutes to observe the result of the …show more content…
This was determined by the change of color in the starch. The hypothesis in this experiment is the same as the result of the experiment. The hypothesis was that the color inside of the bag would change because iodine would go into the bag. The plastic bag is selectively permeable because it allowed the iodine to enter the bag but didn’t allow the starch to pass through the bag. Diffusion is the movement of particles from a high concentration to a low concentration. Starch did not pass through because the starch molecules are too large to pass through the membrane or in this experiment, the bag. The result of this lab is significant to science because it shows how small materials enter the cell and it also further explains selective permeability. It also further explains diffusion and how only small and charged molecules can enter the cell. A suggested follow up would be if you would switch the iodine and the starch. This means that the iodine would be inside of the bag and the starch would be on the outside. This would then kind of prove the result for this
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