Protoplasm is the living substance found within cells, consisting of a gel-like fluid called cytoplasm and the nucleus. It is essential for the life processes of all living organisms, as it contains the necessary components for cellular functions, such as proteins, lipids, and nucleic acids. In addition to providing structure, protoplasm plays a crucial role in metabolism, growth, and reproduction. It facilitates the movement of materials within the cell and supports the activities of organelles, which are specialized structures that perform specific functions. Understanding protoplasm is fundamental to the study of cell biology.