ACTIVITY 40: A CELL MODEL

Record each step of this experiment in your notebook.

BACKGROUND KNOWLDEGE

Important Vocabulary:

Cytoplasm – jelly likeSubstance that fills much Of the inside of a cell.

Cell membrane – part of a cell that separates itfrom Other cells and it’s environment.

QUESTIONWhat is the function of a cell membrane?

RESEARCH Add research into your notebook here.

Include information you learned from the background knowledge page as well as any facts you know from other classes or experiences you’ve had that would help you understand how the cell membrane works.

Write at least 2 pieces of information here.

PROCEDURE Read the procedure on the following slides. While you read, create a comic strip that shows the steps you will take to create this model.

PROCEDURE1. Label two plastic cups “Cup 1” and “Cup 2”.2. Use the graduated cup to pour 100 ml of water into each of these cups.3. Add 7 drops of Lugol’s solution to Cup 1.4. Add 1 level teaspoon of cornstarch to Cup 2 and stir until mixed.5a. Use the graduated cup to pur 30 ml of water into a sandwich bag. Then add 7 drops of Lugol’s Solution to the water in the bag.5b. Use the graduated cup to mix 30 ml of water with one teaspoon of cornstarch. Stir and then carefully pour the mixture into a sandwich bag. Be careful to avoid getting cornstarch on the outside of the bag. If there is cornstarch on the outside of the bag, rinse the bag under cold water.6. Use rubber bands to seal the bags.

PROCEDURE7. Place the bag containing cornstarch into Cup 1 and the bag containing Lugol’s solution into Cup 2 as shown.

8.Place the cups on a sheet of

White paper and leave them thereFor 10-15 min.

Draw the above diagram in your notebook and label the contents of the cups and bags.

DATA TABLE Create a data table in your notebook to record the initial and final color of each solution, both inside and outside the bag.

RESULTS View the before and after photos on the

following two slides and record your observations in your data table in your notebook.

Lugol’s solution is an indicator of starch. When you see a dark purple or blackish color, that means that Lugol’s solution is coming in contact with starch. Think about how this would have happened.

RESULTS Before:

RESULTS After:

CONCLUSION In your notebook, tell what the function

of a cell membrane is, based on the results from this lab. There are three important functions. Be sure to include evidence from your results to support your claim.