A Cell Model

Modeling Diffusion/Osmosis

(SALI activity)

Analysis:

1.    Draw a diagram of the cell model used in this activity.  Label the following:

        cell membrane, environment, cytoplasm, iodine, cornstarch.

2.    Let the 2 cups sit for 30 minutes. 

        Cup A:   Which part of the set-up showed a reaction between the iodine

                    and the starch?

        Cup B:    Which part of the set-up showed a reaction between the iodine

                      and the starch?

3.    Which particles- starch or iodine- were able to cross the model of the

        cell membrane?  Support your answer.

        Which particles- starch or iodine- were unable to cross the model cell

        membrane?  Support your answer.

4.    Based on your cell model, what is the function of the cell membrane?

5.    Why is it important  for molecules to be able to pass through the cell

        membrane?

6.    Illustrate the result of the reactions in each cup.

7.    Briefly explain how iodine is used as an "indicator".  Be sure to mention

        another activity that we did in class that helped you understand this

        concept.

BONUS!!

   Molecules move from an area of greater to lesser concentration. 

        We discussed this concept during our "weather" unit in grade 6. Briefly

        explain the "weather" lesson that relates to this.