When you need to make a representation of a plant or animal cell for a science project, it usually needs to be rendered in three dimensions. Completing a 3-D cell doesn't need to be expensive. You can use everyday materials to make an inexpensive salt dough for the body of the cell.
Mix 1 cup flour, 1/2 cup salt and 1/2 cup water in a bowl until they are completely blended. This mixture will be used to create your cytoplasm. Add a few drops of food colouring, if desired.
Spread the dough on the cardboard sheet. Make sure that you create an even layer that is 1/4 inch thick. Use this to make an oval or circle for an animal cell and a square or rectangle for a plant cell.
While the dough is still wet, press small objects into it to create organelles. Items like multicoloured pony beads or yarn work well because they will stick into the dough without glue or tape. Some organelles you can add are the cell wall, cell membrane, mitochondria, vacuoles, ribosomes, nucleus, nuclear membrane, nucleolus, chloroplasts, lysosomes, centrosomes, endoplasmic reticulum and Golgi bodies.
Reserve a small object from each type of organelle. Use these objects to create a key on the side of the cardboard. Glue each object on the cardboard. Use a marker to identify what each item represents.
Allow the project to dry overnight.
Add more flour to the dough if it is too runny.
Don't use food ingredients that could rot to represent your organelles.