Eukaryotic cells are complex cells that contain membrane-bound organelles, including a nucleus, mitochondria, endoplasmic reticulum, and Golgi apparatus. These cells make up plants, animals, fungi, and protists, enabling higher biological functions such as specialization and multicellularity. Each organelle within a eukaryotic cell has a distinct role, from energy production to genetic storage. Understanding eukaryotic cells is key to studying advanced life forms and their biological processes.