BIOLOGY | Sunday Observer


Cell Nucleus

The nucleus is perhaps the most important structure inside animal and plant cells. It is the main control center for the cell and acts kind of like the cell's brain. Only eukaryotic cells have a nucleus. In fact, the definition of a eukaryotic cell is that it contains a nucleus while a prokaryotic cell is defined as not having a nucleus.


The nucleus is an organelle within the cell. This means it has a special function and is surrounded by a membrane that protects it from the rest of the cell. It floats within the cytoplasm (the fluid inside the cell).

How many nuclei are in a cell?

Most cells only have one nucleus. It would get confusing if there were two brains! However, there are some cells that develop with more than one nucleus. It's not common, but it does happen.



Genetic Information

The most important function of the nucleus is to store the cell's genetic information in the form of DNA. DNA holds the instructions for how the cell should work. DNA stands for deoxyribonucleic acid. The molecules of DNA are organized into special structures called chromosomes. Sections of DNA are called genes which hold hereditary information such as eye color and height. You can go here to learn more about DNA and chromosomes.