Cell growth is the process by which cells increase in size and then multiply to form new cells. In most living systems, growth happens not by one cell becoming huge, but by a carefully timed sequence that creates more cells overall. As a cell grows, it doubles up its essential machinery—DNA, proteins, and energy producers—so that two healthy daughter cells can emerge after division. The idea of cell growth covers both a cell expanding its own contents and tissues gaining more cells through division. How do cells multiply? It follows the cell cycle, a built-in schedule that coordinates growth, DNA replication, and division. In the G1 phase, a cell grows and prepares, then copies its DNA during the S phase. In G2, it readies for division, and the final steps—mitosis and cytokinesis—split the cell into two. During DNA replication, the genetic material is copied so each new cell receives a complete set of instructions. Mitosis ensures chromosomes are distributed evenly, while cytokinesis completes the split, yielding two separate cells ready to grow again or take on new duties. Why does division matter? Cell growth through division drives development from embryo to adult, supports tissue renewal, and enables repair after injury. Tissues constantly balance growth with loss, so organs maintain their size and function. When all goes well, growth keeps pace with demand, helping the body stay organized and capable. What it means for health and disease can come down to regulation. Cells rely on signals and checkpoints to keep growth under control, allowing division only when conditions are right. If this regulation falters, cell growth can become abnormal, leading to unusual growth patterns in tissues. By exploring cell growth, scientists gain insight into how normal development works and how disruptions in growth regulation can be linked to disease contexts.
