This document discusses the structure and organelles of the cell. It describes the cell theory that all living things are composed of cells, cells are the basic unit of life, and new cells are produced from existing cells. It then explains the structure and functions of the major organelles in eukaryotic cells, including the nucleus that contains DNA, ribosomes that produce proteins, the endoplasmic reticulum and Golgi apparatus that process proteins, mitochondria that generate energy, and the cell membrane that regulates what enters and exits the cell. It also covers cellular processes like diffusion, osmosis, active transport, endocytosis, and exocytosis.