An animal cell, a fundamental unit in animal biology, is a eukaryotic cell encapsulated by a lipid bilayer called the cell membrane. This structure houses a nucleus with genetic material, DNA, orchestrating cellular activities. Mitochondria, often called the cell's "powerhouses," generate energy. The endoplasmic reticulum plays a role in protein synthesis and lipid metabolism, with rough and smooth ER subtypes. The Golgi apparatus processes and packages molecules, while lysosomes contain digestive enzymes. Ribosomes are responsible for protein synthesis. A complex cytoskeleton provides structural support and enables cell movement and division. Centrioles aid in cell division. These cells exhibit remarkable diversity, adapting to various functions and tissues within the animal kingdom.