What is an Animal Cell? If you want to know what an animal cell is, you first need to know what a cell is. Cells connect to create tissue and perform functions. The term "cell" was first used by Robert Hooke in 1665. Hooke was an influential English scientist and philosopher during the 17th century (Shapin, 1989). It is also important to understand the unified cell theory when talking about what a cell is. The unified cell theory was proposed by Matthias Schleiden and Theodor Schwann in 1830. It outlines three important things about cells: 1. All living things are composed of one or more cells. 2. The cell is the basic unit of life. 3. All new cells come from o nes that already exist through cellular division. Types of cells There are two kinds of cells, prokaryotic and eukaryotic. Prokaryotic cells are single celled or unicellular organisms. This type of cell includes things like bacteria cells. However, Eukaryotic cells are multicellular organisms that in