L11. Cell Division: Making New Cells

Growth, Reproduction, and Development

R-report

L11. Cell Division: Making New Cells

A tiny cut on your finger can close in a few days. How does your body make enough new cells to replace the ones that are damaged?

Cells grow before they divide

A cell does not simply split whenever it feels crowded. Before division, it grows, copies its DNA, and checks that it has enough materials and energy. DNA contains instructions for building and running the cell. Making a complete copy gives each future cell a full set of instructions instead of leaving one cell with only half a plan.

Mitosis separates copied chromosomes

During mitosis, the copied DNA coils into visible chromosomes. Spindle fibers line the copies up in the middle of the cell and pull one copy to each side. The nucleus then forms around each complete set. The cell has carefully divided the instructions so both new cells can work correctly.

Cytokinesis finishes the split

After the DNA has been separated, cytokinesis divides the rest of the cell. An animal cell pinches inward like a soft balloon, while a plant cell builds a new cell wall between the two sides. The result is two daughter cells that are usually the same size and carry the same genetic information as the original cell.

One cell becomes two working cells

Cell division is a carefully ordered process: grow, copy the DNA, separate the copies, and divide the cell body. Each daughter cell receives the same instruction set, which lets an organism grow and replace worn-out or damaged cells.

The process is controlled because division is powerful. If cells divide when they should not, tissues can grow abnormally. Checkpoints help a cell pause and repair mistakes before it continues.