Nucleus

Nucleus is a term used in various fields of science, but in the context of biology, it refers to a membrane-bound organelle found in eukaryotic cells. The nucleus contains the majority of the cell's genetic material in the form of multiple linear DNA molecules organized into structures called chromosomes.

Structure

The nucleus is the largest organelle in the cell and is surrounded by a structure called the nuclear envelope. This envelope separates the contents of the nucleus from the rest of the cell. The nuclear envelope is made up of two lipid bilayer membranes. The outer membrane is continuous with the endoplasmic reticulum (ER) and may be studded with ribosomes. The space between the membranes is called the perinuclear space and is continuous with the ER lumen.

Function

The nucleus controls and regulates the activities of the cell (e.g., growth and metabolism) and carries the genes, structures that contain the hereditary information. Nucleoli are structures found within the nucleus that are a center of production of ribosomes, the cell's protein-synthesizing machinery.

History

The nucleus was the first organelle to be discovered. What is most likely the oldest preserved drawing dates back to the early microscopist Antonie van Leeuwenhoek (1632–1723). He observed a "lumen", the nucleus, in the red blood cells of salmon.

See also

• Cell (biology)
• Chromosome
• DNA
• Nuclear envelope
• Nuclear pore
• Nucleolus