The Nucleolus
The Nucleolus

http://www.enchantedlearning.com/subjects/plants/cell/ nucleolus- an organelle within the nucleus - it is where ribosomal RNA is produced. nucleolus: The prominent structure in the nucleus is the nucleolus. The nucleolus produces ribosomes, which move out of the nucleus and take positions on the rough endoplasmic reticulum where they are critical in protein synthesis
nucleus
nucleus
Nucleolus


The prominent structure in the nucleus is the nucleolus. The nucleolus produces ribosomes, which move out of the nucleus to positions on the rough endoplasmic reticulum where they are critical in protein synthesis.
http://www.cellsalive.com/cells/nucleus.htm
The nucleolus is a prominent sub-nuclear structure that is not bound by a membrane and resides within the nuclear matrix. Though known to exist since the eighteenth century, the primary function of the nucleolus was not discovered until the 1960s. It is now been determined that nucleoli manufacture the subunits that combine to form ribosomes, the cell's protein-producing factories. Accordingly, the size of nucleoli depends upon the ribosomal requirements of the type of cell in which they are found. In cells that produce large amounts of protein, and thus call for significant numbers of ribosomes, the size of the nucleolus is considerable, sometimes occupying as much as 25 percent of the total volume of the nucleus.
http://micro.magnet.fsu.edu/cells/nucleus/nucleolus.html
Nucleolus - Plant

History

John Gurdon and Donald Brown generated the first interest in cell nucleoli in 1964, when they discovered them in the African clawed frog Xenopus laevis. They found that 25% of the frog eggs had no nucleolus and that such eggs were not capable of life. Half of the eggs had one nucleolus and 25% had two. They concluded that the nucleolus had a function necessary for life. In 1966 Max L. Birnstien and Hugh Wallace showed via hybridization experiments that nucleoli code for ribosomal DNA. Within the nucleus are one or more nucleoli. The nucleolus is roughly spherical, and appears as a mass of densely stained granules and fibres under an electron microscope. It consists of nucleolar organizers. They are specialized regions of some chromosomes with multiple copies of genes for ribosome synthesis, along with a considerable amount of RNA and proteins representing ribosomes in various stages of production. An average, healthy cell can produce up to 10 000 ribosomes per minute.The nucleolus contains all the dna of the cell. It is sometimes refered to as the brain because it controlls what goes on.
http://en.wikipedia.org/wiki/Nucleolus


external image Nucleolus30.jpg
The nucleolus is roughly spherical, and appears as a mass of densely stained granules and fibres under an electron microscope. It consists of nucleolar organizers. They are specialized regions of some chromosomes with multiple copies of genes for ribosome synthesis, along with a considerable amount of RNA and proteins representing ribosomes in various stages of production. An average, healthy cell can produce up to 10 000 ribosomes per minute. http://www.stemnet.nf.ca/~dpower/cell/ncleolus.htm


Video


Nucleolus is on at 3:25




A small, typically round granular body composed of protein and RNA in the nucleus of a cell. It is usually associated with a specific chromosomal site and involved in ribosomal RNA synthesis and the formation of ribosomes. http://www.answers.com/topic/nucleolus The Nucleolus - The nucleolus is the densest region of chromatin that is responsible for the synthesis of ribosomes. A nucleus may contain multiple nucleoli, but within each species the number of nucleoli appears to be fixed. The nucleolus is morphologically separated into three distinct components; fibrillar centres (FC) - containing hundreds of rRNA genes in tandem arrays found at several chromosomal loci (termed nucleolar organising regions (NORs); the dense fibrillar component (DFC), which contains actively transcribing rRNA genes and nascent rRNA transcripts; and the granular component (GC), which is the site of late processing events in the biogenesis of rRNAs [4]. The nucleolus is also responsible for the trafficking of various small RNA species and has been implicated in the control of cellular survival and proliferation and senescence [5].http://www.illuminatedcell.com/Nucleus.html **Nucleolus:** Dark-staining body within the nucleus where ribosomal RNA is synthesized. Plant nuclei in onion root tip cells may have several nucleoli.

The nucleolus is a prominent sub-nuclear structure that is not bound by a membrane and resides within the nuclear matrix. Though known to exist since the eighteenth century, the primary function of the nucleolus was not discovered until the 1960s. It is now been determined that nucleoli manufacture the subunits that combine to form ribosomes, the cell's protein-producing factories. Accordingly, the size of nucleoli depends upon the ribosomal requirements of the type of cell in which they are found. In cells that produce large amounts of protein, and thus call for significant numbers of ribosomes, the size of the nucleolus is considerable, sometimes occupying as much as 25 percent of the total volume of the nucleus.where i got this info^
external image nucleolus.jpg
- Spherical shape
- Visible when cell is not dividing
- Contains RNA for protein manufactur website.

Nucleolus, structure within the nucleus of cells, involved in the manufacture of ribosomes (cell structures where protein synthesis occurs). Each cell nucleus typically contains one or more nucleoli, which appear as irregularly shaped fibers and granules embedded in the nucleus. There is no membrane separating the nucleolus from the rest of the nucleus.

external image nucleo.gif
Within the nucleus are found chromatin and a structure called the nucleolus. Chromatin is DNA in its active form. It consists of DNA looped around histone proteins. The nucleolus is a knot of chromatin. It is the nucleolus that manufactures ribosomes


nucleolus
nucleolus

The nucleolus is the dark circle within the larger mottled circle of the nucleus ----
The site of ribosomal RNA (rRNA) synthesis in eukaryotic cells. The nucleolus is spherical in shape and made up principally of rRNA that is in the process of being transcribed from rRNA genes. It is surrounded by the nuclear membrane.
Nucleolus
Nucleolus


Nucleolus: Dark-staining body within the nucleus where ribosomal RNA is synthesized. Plant nuclei in onion root tip cells may have several nucleoli.

external image nucleolus.jpeg