Cellular transport refers to the process by which molecules and other substances are moved in and out of cells. This is crucial for maintaining the internal environment of the cell, regulating the exchange of nutrients and waste, and allowing cells to communicate with each other. There are two main types of cellular transport: passive transport, which does not require energy and includes processes such as diffusion and osmosis, and active transport, which requires energy and involves the movement of molecules against their concentration gradient. Understanding cellular transport is important for studying various biological processes, such as cell signaling, metabolism, and homeostasis.