TIME: 45-75 mins

Part 1: Gel Cells - Modeling the Difference between a Plant and Animal Cell

and

The Organelle Game using Pictionary

Make enough gel cells so each students can make a plant and an animal cell. See attached sheet that lists the most important organelles found in the average cell.

Materials:

Data sheet

The materials used can be everyday household objects. For example:

Rigid cell wall= small plastic, see-though box (try Long's Drugs)

Plasma membrane = plastic bag; for plants it can be cut to fit inside the rigid cell wall box

Vacuole= small water balloon

Chloroplast=flat, green marbles (try Ben Franklin store)

Nucleus= large marble or small rubber ball

Smooth endoplasmic reticulum (ER) = smooth stain ribbon

Ribosomes and rough endoplasmic reticulum (ER) = ribbon with side loops

Mitochondrion = plastic beads

Golgi complex = spongy hair rollers cut into discs

Plasmodesma = small wooden spools (craft store)

Lysosomes = beads

Cytoplasm = clear hair gel (about 4 oz for each cell)

Glue necessary to attach plasmodesma (spool)

CD picture of Plant and Animal Cell

Procedure/Method:

Explain cells and their contents (organelles, just as our bodies have organs). Cells are building blocks of animals and plants. Where did the word "cell come" from? They looked like monks' cells to Robert Hooke. They were discovered as microscopes were invented and improved in the 1800’s.

Point out some of the major differences between plant and animal cells, such as the fact that plants have RIGID CELL WALLS, CHLOROPLASTS, and PLASMODESMA. These organelles help plants stand up (they don’t have bones), make food (they can photosynthesize, or make food from sun and air, unlike animals), and the plasmodesma helps the cells exchange matter through the rigid cell walls. Show pictures of animal and plant cells included on the CD.

Have materials laid out in containers or bags with labels, give student the sheet of cell features and have them make one plant and one animal cell, making sure they circle each organelle as they add it. Have some glue on hand so they can glue the plasmodesma onto the outside of their plant cell. When they are done have them line up and have an adult squeeze in the gel (cytoplasm).

When they are all finished, go over the organelles, and reasons that there are differences between plants and animals. Follow this with a game of Organelle Pictionary (with help from their now completed data sheet) to help solidify organelle names and their purpose.

Part 2: The Wauke Cell – What’s so great about it?

Materials:

Long piece of elastic

Procedure/Method:

Next, bring the activity back to the special features of the wauke inner bark cells, called BAST fibers. Have students look at the plant cell they made. Let them know that if this were an “average” plant cell it would be less than 1/10 of a millimeter in thickness. So, for example, if you stacked up 10 or more of these, they wouldn’t even be as thick as your fingernail. On the other hand, wauke cells are often about 10 mm long, so as wide as my hand. These wauke fibers are BAST fibres and are about 100 times longer than a regular plant cell.

As a demonstration take their plant cell model (if it is about 8 cms or 3” long) and use a long piece of elastic (8 meters or 26’) to show the relative size of a wauke fiber cell. Have a student grasp one end and another stretch it out. Also note that it is more flexible than your average plant cell, making it excellent to use as fabric as it can stretch and is not so rigid.