Place a plastic zip bag in a square plastic container. Choose a container that is typically used as a food saver and that is at least 7 inches wide. The plastic represents the cell membrane of a plant cell, while the plastic container is the cell wall.
Add lemon-flavored powdered gelatin into a large bowl. Lemon works well since it is a light color. Add 2 cups of boiling water and stir to dissolve. Add 2 cups of the cold water. Stir well. Allow the gelatin to cool for at least 20 minutes.
Pour the gelatin into the plastic bag inside the square container. It should be near the top of the bag. Do not overfill. You will be adding other objects as the cell components to the bag. If you have too much gelatin, you can discard the extra.
Cut your plum in half so the pit shows. Add it to the bag as the nucleus and the pit as the nucleolus. Add the mandarin oranges as the mitochondria. Add the green grapes to represent chloroplasts.
Break off pieces of lasagna to become the endoplasmic reticulum. A small piece of cardboard cut into an oval shape is the Golgi body. Add small buttons as vacuoles, and add ground pepper to represent ribosomes.
Zip up the plastic bag to contain your 3-dimensional plant cell model. Refrigerate overnight and bring it to class.