The more complex cell type you are referring to is known as a eukaryotic cell. Eukaryotic cells are characterized by the presence of a well-defined, membrane-enclosed nucleus that houses the cell’s genetic material. In addition to the nucleus, these cells also contain various organelles, such as mitochondria, endoplasmic reticulum, and Golgi apparatus, each performing specific functions necessary for the cell’s life.
Unlike prokaryotic cells, which are simpler and lack a nucleus, eukaryotic cells are typically found in more advanced organisms, including animals, plants, fungi, and protists. The complexity of eukaryotic cells enables them to carry out more specialized functions and processes, making them integral to the functioning of multicellular life forms. This organization allows for a greater range of cellular activities and interactions, further enhancing the biological capabilities of these organisms.