Cell division is how cells reproduce. They might be cells that are a part of a large body (like your skin cells) or cells that are individuals (like an amoeba).

You lose cells from the surface of your skin all the time. Don’t worry though, because deep down in your skin, cells keep dividing to replace them. Some of these cells move up to the surface, while others stay behind to keep dividing. When a single-cell individual divides, it splits in half and each half goes on to be a new individual.

We call the cell that is about to divide mother cell and call the new cells daughter cells. It doesn’t mean they are female, though.

Before a mother cell can divide, it has to make sure that each of the daughter cells will have all that they need. So before a cell divides, it makes does things like copy its DNA. The DNA holds the codes that make a cell work. So each of the daughter cells gets the complete set of instructions. The DNA and other parts of the cell have to be divided up. That process is called mitosis (my-TOE-sis). Then the cell pinches apart in the middle to form the two new daughter cells.

A special kind of cell division happens to make egg or sperm cells. It’s called meiosis (my-OH-sis). The DNA divides twice so that eggs or sperm each have half a portion of DNA. Then when they meet their opposite in fertilization, the embryo has a full set.

Which kinds of cells do you think have to divide a lot and which do you think divide rarely or never?

Cell division is how one cell makes more cells. As a cell goes through its life cycle, it copies its DNA, then splits, forming two identical “daughter” cells.

In eukaryotic cells (such as the cells in plants and animals — including the cells that make up your body), the process of division is called mitosis. During mitosis, the cell’s DNA gets wound up into tightly packed structures called chromosomes. Then the chromosomes get separated half-and-half into each daughter cell, and the cell membrane pinches in the middle until it splits and forms two cells. Because there are two copies of each chromosome, each daughter cell gets one copy of each chromosome, so they both end up with exactly the same DNA as their parent cell.

In prokaryotic cells (such as bacteria), the process is similar, but less complicated. Prokaryotes typically don’t form tightly packed chromosomes like eukaryotes do. And many species of bacteria actually carry many copies of their DNA! When a prokaryotic cell divides, in a process called binary fission, it just makes a new cell wall down the middle of the cell, and then the two halves separate.

If you want to learn more, Khan Academy has a great unit on:
cell division.