external image cellnucleus.jpg

nucleus - a spherical body containing many organelles, including the nucleolus. The nucleus controls many of the functions of the cell (by controlling protein synthesis) and contains DNA (in chromosomes). The nucleus is surrounded by the nuclear membrane Nucleus

http://www.enchantedlearning.com/subjects/plants/cell/
The cell is the basic unit of life. Plant cells are surrounded by a thick, rigid cell wall.
micro.magnet.fsu.edu/cells/plants/nucleus.htmlThe nucleus is a highly specialized organelle that serves as the information and administrative center of the cell. This organelle has two major functions. It stores the cell's hereditary material, or DNA, and it coordinates the cell's activities, which include intermediary metabolism, growth, protein synthesis, and reproduction (cell division).
Nearly every single cell has a nucleus. (Only bacteria and blue-green algae lack a nucleus.) The nucleus controls and regulates the activities of cell. It is also where all genetic information is stored. Most nuclei* are surrounded by a cell membrane. The nucleus shown below is surrounded by a dark- blue membrane. The membrane stops genetic material from floating around inside the cell.

Most of the nuclear material consists of chromatin, the unstructured form of the cell's DNA that will organize to form chromosomes during mitosis or cell division.

The nucleus is a highly specialized, multifunctional organelle serving as the information hub and administrative center of the cell. It is a cohesive centre for nuclear genes aligned on chromosomes and acts as an organizer of cytoplasmic and nuclear activities during the cell cycle. The nucleus helps in shuttling of regulatory factors & gene products via nuclear pores, aids production of mRNAs and ribosomes and organizes the uncoiling of DNA to replicate key genes. It thus coordinates innumerable metabolic pathways to achieve growth, division and differentiation of the cell. The nucleus of the plant cell shows a complex organization [1]. The study of particular proteins in the nucleus of chemically fixed cells aided by fluorescence microscopy uncovered many vital details of nuclear architecture [2]. These studies clearly established the existence of several morphologically distinguishable intra-nuclear structures.http://www.illuminatedcell.com/Nucleus.html

The nucleus is the most prominent feature of a eukaryotic cell – cells that have nuclei. It is quite easy to recognize the nucleus when you look at a cell through microscope as it is an organelle that is enclosed by a membrane, forming a very distinct “center” in the cellular structure. The nucleus houses majority of the genetic material of the cell, particularly the molecules of DNA that are responsible for the control of the cell’s general activity, which in turn expresses the organism’s identity. It is the nucleus that maintains the expression of genes by managing the cell’s activities based on the genetic plan imprinted in the organism

The cell nucleusis a remarkable organelle because it forms the package for our genes and their controlling factors. It functions to:
external image bluedot.jpg Store genes on chromosomes
external image bluedot.jpg Organize genes into chromosomes to allow cell division.
external image bluedot.jpg Transport regulatory factors & gene products via nuclear pores
external image bluedot.jpg Produce messages ( messenger Ribonucleic acid or mRNA) that code for proteins
external image bluedot.jpg Produce ribosomes in the nucleolus
external image bluedot.jpg Organize the [[http://cellbio.utmb.edu/cellbio/nucleus2.htm#4 nm DNA|uncoiling of DNA ]]to replicate key genes

The cell nucleus acts like the brain of the cell. It helps control eating, movement, and reproduction. If it happens in a cell, chances are the nucleus knows about it. The nucleus is not always in the center of the cell. It will be a big dark spot somewhere in the middle of all of the cytoplasm (cytosol). You probably won't find it near the edge of a cell because that might be a dangerous place for the nucleus to be. If you don't remember, the cytoplasm is the fluid that fills cells.
http://www.biology4kids.com/files/cell_nucleus.html

Only the cells of advanced organisms, known as eukaryotes, have a nucleus. Generally there is only one nucleus per cell, but there are exceptions such as slime molds and the Siphonales group of algae. Simpler one-celled organisms (prokaryotes), like the bacteria and cyanobacteria, don't have a nucleus. In these organisms, all the cell's information and administrative functions are dispersed throughout the cytoplasm.
The spherical nucleus occupies about 10 percent of a cell's volume, making it the cell's most prominent feature. Most of the nuclear material consists of chromatin, the unstructured form of the cell's DNA that will organize to form chromosomes during mitosis or cell division. Also inside the nucleus is the nucleolus, an organelle that synthesizes protein-producing macromolecular assemblies called ribosomes.
A double-layered membrane, the nuclear envelope, separates contents of the nucleus from the cellular cytoplasm. The envelope is riddled with holes called nuclear pores that allow specific types and sizes of molecules to pass back and forth between the nucleus and the cytoplasm. It is also attached to a network of tubules, called the endoplasmic reticulum, where protein synthesis occurs. These tubules extend throughout the cell and manufacture the biochemical products that a particular cell type is genetically coded to produce.
where i got this info^

nucleus - spherical body containing many organelles, including the nucleolus. The nucleus controls many of the functions of the cell (by controlling protein synthesis) and contains DNA (in chromosomes). The nucleus is surrounded by the nuclear membrane
where i got this info^

**interactive cell animation**

In cell biology, the nucleus (pl. nuclei; from Latin nucleus or nuculeus, or kernel) is a membrane-enclosed organelle found in all 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 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.
http://en.wikipedia.org/wiki/Cell_nucleus

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http://cellbio.utmb.edu/cellbio/nucleus.htm