Search results
Results from the WOW.Com Content Network
The cell nucleus (from Latin nucleus or nuculeus 'kernel, seed'; pl.: nuclei) is a membrane-bound organelle found in eukaryotic cells. Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells , have no nuclei , and a few others including osteoclasts have many .
The protoplasmic material of the nucleus including the nucleolus labelled as nucleoplasm. The nucleoplasm, also known as karyoplasm, [1] is the type of protoplasm that makes up the cell nucleus, the most prominent organelle of the eukaryotic cell. It is enclosed by the nuclear envelope, also known as the nuclear membrane. [2]
In biology, the nuclear matrix is the network of fibres found throughout the inside of a cell nucleus after a specific method of chemical extraction. According to some it is somewhat analogous to the cell cytoskeleton. In contrast to the cytoskeleton, however, the nuclear matrix has been proposed to be a dynamic structure.
Hence, the cell has a number of mechanisms in place to control how DNA is organized. [4] Moreover, nuclear organization can play a role in establishing cell identity. Cells within an organism have near identical nucleic acid sequences, but often exhibit different phenotypes. One way in which this individuality occurs is through changes in ...
The entry and exit of large molecules from the cell nucleus is tightly controlled by the nuclear pore complexes (NPCs). Although small molecules can enter the nucleus without regulation, [ 1 ] macromolecules such as RNA and proteins require association with transport factors known as nuclear transport receptors , like karyopherins called ...
The nuclear envelope, also known as the nuclear membrane, [1] [a] is made up of two lipid bilayer membranes that in eukaryotic cells surround the nucleus, which encloses the genetic material. The nuclear envelope consists of two lipid bilayer membranes: an inner nuclear membrane and an outer nuclear membrane. [ 4 ]
Most important among these is a cell nucleus, [2] an organelle that houses the cell's DNA. This nucleus gives the eukaryote its name, which means "true kernel (nucleus)". Some of the other differences are: The plasma membrane resembles that of prokaryotes in function, with minor differences in the setup. Cell walls may or may not be present.
Macronuclei and micronuclei differ in their functions even though they are located within the same cell. The micronucleus is globally repressed during the vegetative state, and serves as the diploid germline nucleus, whereas all known vegetative gene expression happens in the macronucleus, which is a polyploid somatic nucleus. [3]