Demonstration #1: Egg
The largest cell within any organism is the female sex cell, the egg. A chicken’s egg is just one large cell.
Vinegar is used to remove the calcium from the eggshell. This softens the shell and exposes the cell membrane,
which allows some materials to enter or leave the egg.
Procedure: Your teacher decalcified these particular eggs 3 days ago and then put one egg into corn syrup and
one egg into 100% pure water for 48 hours.
1. Record your observations of the two eggs and draw the direction of the movement of water into/out of
the egg.
2. What would be your control in this experiment and why?
3. Using and defining all appropriate vocabulary (Osmosis, cell membrane, concentration, equilibrium
Brownian movement, passive transport), explain what happened to the eggs AND why it happened?
Also, explain the need for this type of transport.
Demonstration #2: Lettuce
1. Record your observations of the lettuce (go ahead and touch it!):
Pure water:
Salt water:
2. Draw a picture of how the lettuce cells above would look. Go back to your picture of plant cells in your
notes if you need to.
3. Based on your observations about the lettuce and your knowledge about osmosis. Please explain to a
restaurant chef (who knows nothing about biology) why he would not want to put salad dressing on his
salad until right before serving.
Demonstration #3: Animations
Watch the following video on Active vs. Passive Transport – start at 5 minutes and watch 10:50.
http://www.youtube.com/watch?v=dPKvHrD1eS4
1. When a cell requires Active Transport – what is the form of energy the cell uses to do this type of
transport?
2. Why is it important that a cell has the ability to do active transport as well as passive transport?
3.
The video discussed the “Sodium Potassium Pump”, what type of Active transport is this illustrating?
4. What is the example of exocytosis shown in the video? Please draw and label the picture to illustrate
what happens in this process.
5. What is the example of phagocytosis shown in the video? Please draw and label the picture to illustrate
what happens in this process.
6. What is the example of pinocytosis shown in the video? Please draw and label the picture to illustrate
what happens in this process.