These cells also contain a large central vacuole that when filled with water is integral to plant support. Animal cells, on the other hand, vary greatly in their shapes. The outer covering, called a cell membrane, is not nearly as rigid as a cell wall. The nucleus is small, but darker than the cytoplasm, and is easily seen under staining. Animal cells, like those found in the cheek, appear empty when compared to plant cells because the parts of animal cells are too small to see even under the highest power of the microscopes used.
Protists are in a class of their own.
These are one-celled creatures that can function on their own, a unique feature of there three kinds of cells. They often have strange shapes that can move and adjust, such as the amoeba, because they have an outer membrane instead of a cell wall. Often, protists have cilia or flagella to aide with cell movement and intake of food. Protists can have properties of both plants and animals at the same time, as is the case in the euglena. This lab served as an aid to examining what makes the cells of plants, animals, and protists similar and what makes them different and unique.