Animal cells are eukaryotic cells, or cells that contain a membrane-bound nucleus. The nucleus holds the DNA of the cell that provides the cell with instructions for life.
In an animal, the cells go through constant mitosis to divide and multiply. This works to guarantee that offspring are genetically identical to the parents. Animal cells also undergo meiosis to ensure the formation of haploid cells. Haploid cells form either eggs or sperm, and these work to form a new diploid cell when one egg and one sperm meet for fertilization. The process of mitosis comes in again to divide the fertilized cell for new organism formation.