Radiology & Imaging

Quantum technology for cancer imaging

Tracing the metabolism of tumor cells using magnetic resonance imaging (MRI) has not been feasible in routine clinical settings hitherto. Now, an interdisciplinary research team including the Technical University of Munich ...

Neuroscience

The role of the cerebellum in absence seizures

Stimulation of certain cerebellar areas could help combat absence seizures. However, what happens at the cellular and molecular level in the brain in this form of epilepsy and how exactly stimulation has an effect is not ...

Medical research

Digging deep for differences in Duchenne muscular dystrophy

A UT Southwestern research team has cataloged gene activity in the skeletal muscle of mice, comparing healthy animals to those carrying a genetic mutation that causes Duchenne muscular dystrophy (DMD) in humans. The findings, ...

Medical research

Study reveals surprising variability of muscle cells

Usually, each cell has exactly one nucleus. But the cells of our skeletal muscles are different: These long, fibrous cells have a comparatively large cytoplasm that contains hundreds of nuclei. But up to now, we have known ...

page 1 from 3

Cell nucleus

In cell biology, the nucleus (pl. nuclei; from Latin nucleus or nuculeus, or kernel), also sometimes referred to as the "control center", is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these chromosomes are the cell's nuclear genome. The function of the nucleus is to maintain the integrity of these genes and to control the activities of the cell by regulating gene expression--the nucleus is therefore the control center of the cell.

The main structures making up the nucleus are the nuclear envelope, a double membrane that encloses the entire organelle and separates its contents from the cellular cytoplasm, and the nuclear lamina, a meshwork within the nucleus that adds mechanical support, much like the cytoskeleton supports the cell as a whole. Because the nuclear membrane is impermeable to most molecules, nuclear pores are required to allow movement of molecules across the envelope. These pores cross both of the membranes, providing a channel that allows free movement of small molecules and ions. The movement of larger molecules such as proteins is carefully controlled, and requires active transport regulated by carrier proteins. Nuclear transport is crucial to cell function, as movement through the pores is required for both gene expression and chromosomal maintenance.

Although the interior of the nucleus does not contain any membrane-bound subcompartments, its contents are not uniform, and a number of subnuclear bodies exist, made up of unique proteins, RNA molecules, and particular parts of the chromosomes. The best known of these is the nucleolus, which is mainly involved in the assembly of ribosomes. After being produced in the nucleolus, ribosomes are exported to the cytoplasm where they translate mRNA.

This text uses material from Wikipedia, licensed under CC BY-SA