This activity is adapted from one designed by Kate Hayne of Soroco Junior High (Oak Creek, Colaradoo). The lesson plan for the original can be found by clicking here

There are many variations on this theme but the basic idea is that the teacher makes up some 'cells' from gelatine and then the students cut them up and note the sizes of the organelles which are then compared to how big the organelles are in a theoretical cell. The aim of this activity is to familiarise the students with the structure of cells and give them some way of relating to the size of organelles. It also proves that Biology can be fun.

Basic Gelatine Mixture

Add gelatine (20ml) to cold water (100ml).

Allow gelatine to swell (4 minutes).

Add boiling water (100ml) and stir.

Gelatine should dissolve, if it does not, microwave on high for 30 seconds.

Allow to cool to room temperature (15-20 mins)

Making the Organelles

Take the liquid gelatine and pour it into flat dishes lined with cling wrap (Petri Dishes are good, small tart dishes are better !)

Put in fridge to set (DO NOT FREEZE).

When set, cut out organelles using either a cookie cutter or a knife.

For the nucleus pour gelatine into a plastic cup and refrigerate, when solid use a melon baller to out spheres.

Cell Assembly

Line square plastic containers with a small plastic bag, pour in about two centimeters of gelatine and refrigerate.

When layer is set, add nucleus and some other organelles, add more gelatine and refrigerate again.

continue to do this until the cell is formed.

Ideas for Organelles

For plant cells, use square plastic containers (about 200ml, with square base 5cm width), this will represent the cell wall.

For animal cells, just use a plastic bag minus the container, this represents the cell membrane.

Can use spaghetti for endoplasmic reticulum and golgi bodies, poppy seeds make great ribosomes and pepper corns can be used to represent centrioles.

In Class

To cut up the cells use plastic knives and plates, the great thing about using gelatine for these is that when the class is finished the cells are easily disposed of by washing them down the sink with hot water.

Students work in twos cutting up cells and measuring organelles, place animal and plant cells in front of alternate pairs so that the pairs can swop information about the size of choloroplasts, cell walls and centrioles. It is important to stress that the numbers they are comparing the organelles to are of a typical cell but that cells differ widely in their structure (can show pictures of red blood cells, nerve cells and paramecium to hammer home the point.)

The questions to the worksheet should be done individually, the answers can then be discussed as a group.

Click here for the student worksheet.