Introduction to Cell Division

Cell division is when one cell divides to form two cells. It is the process by which new cells are made.

Electron microscope image of a cell in the process of dividing. It is a black and white image. The cell is a unicellular organism. In the bottom right corner there is a smaller image of a cell at the same stage of division. This image is in colour and was captured using a light microscope.

A cell in the process of dividing. The main image was captured with an electron microscope. The smaller image in the corner was captured with a light microscope. Image: Allisonmlewis on Wikimedia Commons (CC BY-SA 4.0 - https://creativecommons.org/licenses/by-sa/4.0/deed.en)

The process of cell division is different in prokaryotic cells and eukaryotic cells. However, there are some things that they have in common.

On this page, we will look at the aspects of cell division that apply to all organisms. Then, on the next page, we will look specifically at cell division in eukaryotes. On the page after that, we will look specifically at cell division in prokaryotes.

Before a cell divides, it usually grows, copies its sub-cellular structures, and copies its DNA

In both prokaryotic and eukaryotic cells, there are certain things that usually happen before a cell divides. These are the following:

  • The cell grows.
  • Sub-cellular structures (e.g. mitochondria in eukaryotes, and ribosomes in both eukaryotes and prokaryotes) are copied to make more of them.
  • The DNA is copied.

Once these things have taken place, the cell divides.

Cells can divide repeatedly in a process called the cell cycle

In both prokaryotes and eukaryotes, these steps can take place repeatedly. In other words, a cell grows, copies its sub-cellular structures and DNA, and then divides to form two cells. Each of those two cells then grows, copies its sub-cellular structures, and divides, resulting in a total of four cells. Each of those cells then does the same, and so on.

This repeating process is called the cell cycle.

On the next page we will look in more detail at the cell cycle in eukaryotes. After that, we will look at the cell cycle in prokaryotes.

Electron microscope image of bacterial cells. Each cell appears roughly spherical in shape. They have been coloured in yellow using a computer. Behind them there is a large, purple cell. This is actually a white blood cell which is in the process of engulfing the bacterial cells.

Bacterial cells. Like the cells of all organisms, they are able to repeatedly divide and grow in a process called the cell cycle. This image was captured with an electron microscope. The colours have been added artificially on a computer.

Flashcards

Flashcards help you memorise information quickly. Copy each question onto its own flashcard and then write the answer on the other side. Testing yourself on these regularly will enable you to learn much more quickly than just reading and making notes.

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What is cell division?

2/3

What things usually happen before a cell divides?

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What is the cell cycle?

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