Cells are the basic building blocks of all living organisms. There are two main types of cells: prokaryotic and eukaryotic. Prokaryotic cells, like those found in bacteria, are simple and do not have a nucleus or other membrane-bound organelles. They are usually smaller and can reproduce quickly. Eukaryotic cells, found in organisms like plants, animals, and fungi, are more complex. They have a defined nucleus that houses their genetic material and various organelles that perform specific functions. This complexity allows eukaryotic cells to carry out more specialized tasks, making them essential for the development of multicellular life.