What is Nucleus? | Nucleus Function And Cell Structure | Definition
What is Nucleus? | Nucleus Function And Cell Structure | Definition
Nucleus Definition: Nucleus is the organism of the cell. Each of the protozoans in the evolutionary cell contains more dense and relatively clear organs and which consists of genealogy carriers, chromosomes, and controls all functions of the cell, called nucleus. In 1831, Robert Brown discovered the nucleus from the orchid leaf cell and named it.
Nucleus: The part of the protoplanel that is relatively dense, surrounded by round and coating and consists of genetic material or chromatin substance (DNA), which is considered as nucleus.
Scientist Robert Brown invented the nucleus in 1831.
Because of the control of all biological functions of the nucleus cells (eg metabolism, cell division, boom and circulation of hereditary properties), it is also called cell brain.
In the primordial cells, the prokaryotic cells do not have a nucleus coating, so the genetic material or chromatin substance stays in DNA cytoplasm.
Although there is no nucleus in prokaryotic or primitive cells, there is usually a nucleus in the center of eukaryotic or genus cells. But depending on the situation of metabolism, depending on the condition of the center can move towards the circumference. Because of the larger cell hole, the nucleus of the plant cell is naturally on the circumference.
Sieve tube nucleus is not present in mammalian organisms, in red blood cells and in the flora of high-grade plants.
Although it is usually spherical, it can be oval or oval or disconnected based on the size of the cell.
Average volume 4 – 2000 cubic micron The cells in mature cells and growing cells are relatively larger in their cells.
Chemical composition: Nucleic acids (DNA: D-oxyibero nucleic acid and RNA: ribbon nucleic acids), proteins (nucleoprotein, nucleoshystone, nonhystone, nuclei enzyme etc.) and various types of mineral salt (phosphorus, potassium, sodium, calcium and magnesium) Composed.
Physical structure: Before the start of cell division, it is found that the four main parts of the interface are found.
Nucleus Function Structure :
A nuclair membren
G. Nucleosolas and
D Chromatin fiber
A neuralar membrane:
Each nucleus is enclosed by a vibrant and twisted screen. The curtain on the edges is called the outer screen and the inner screen is called the interior screen. The space between the two screens is called perinocular, whose width is 10-15 nanometers or millimycrans.
There is a 40-145 hole per square micrometre of animal magnetic nuclei membrane. Holes are octagonal and diameter of 60 nanometers or millimeters. The round area around the hole is known as annuli. Hud and Anuli together are Poor Complex, which controls the movement of various objects between nucleus and cytoplasm.
Function: Providing and maintaining the shape of the nucleus. Control the movement of different objects.
Semi-liquid, transparent and granulated fluid substances located between the nucleus membranes and nucleosol. It is called nucleus juice or karyolymph.
The chromaton reticulum is in motion. It also contains DNA, RNA, phospho-protein, histone, enzyme, or mineral salt.
Works as a nucleus brew.
In 1781 the scientist Fantana (Fontana) first described the nucleosol, which is mainly composed of phospho-proteins and RNA. The smaller and more dense circular objects seen in nuclei are nucleosolas.
The nucleus usually consists of three parts. Such as: Grainy part of the middle, chromatin and maternal part.
It is chemically formed by proteins, RNA and little by DNA.
It is the most dense part of the nucleus, in which four areas are found. Namely
Granular zone: This granulated area of ribonucleoprotein is located in the nucleus area.
Fibrillar zone: A formulaic region called ribonucleo proteins called nucleolonema.
Amorphous zone: It is a low-electron density region.
Croatin region of the interior and outer nuclei: DNA-formulated objects, which are located in the area of chromatin, which is located in the nucleus area
Work: Creating Rhizome. RNA and protein synthesis.
D. Cormatine fiber
The inside of the nucleus is trimmed objects like chrysantine fibers. When cellulose is separated into chromosomes, they are called chromosomes, when chromatin tuncules are relatively small, continuously humid and visible.
Each chromosome has one or more centromere, chromonema, placental, dirt and any satellites.
Chemically, each chromosome consists of DNA, RNA, histone, and nonhistone proteins.
Nuclear Reticulum or Chromatin Fibers:
Nucleopulose contains nucleic acids (DNA and RNA) and many long and formidable fibers formed in proteins, which are known as chromatin tantra.
Scientist Felmming named chromatin in 1879 as a formula for fibers called nucleiplazzom.
When the chromatin fibers spread in the nuclei, they are called the Nuclear Reticulum.
The fibers are formed in intermediate stage of the cell division and in the stage of conformation, the conformation becomes known as chromosome, which is known as chromosome.
The portion of the chromatin fibers that contain the color in the color is heterochromatin, and the color that does not contain the color is called euchromatin.
Functions: To hold genetic material (DNA) and to construct chromosomes during cell division.
The chromotin fibers are converted to cell division into the formation of a deciduous structure into chromosomes, which contain all the properties of the organism, and through this the characteristics are transmitted to the progeny.
In 1888, the scientist Waldeyer named the chromaton in the formation of the decaying structure found in the phase of cell division in chromosomes.
In 1933, the scientist Bovery proved that chromosomes are the inheritors and carriers.
In 1935, the scientist Heitz first described the formation of chromosomes.
In 1966, the scientist Dupraw described the fine structure of chromosomes.
Chromosomes in length 0.2 – 50 microns (μ) or micrometer (μm) and width 0.2 – 2 micron (μ) or micrometer (μm). The length of human chromosomes is 6 micron (μ) or micrometer (μm).
Containing deoxyribonucleic acids or DNA or genes molecules.
Protein synthesis through DNA.
Number of chromosomes:
Chromosomes are specific to a particular species.
In the same species, the genome (sperm and ova) of the genus is about half of the chromosomal number of cells that are called gametic single mass or haploid set (which is expressed by n).
On the other hand, a gametic bi-digit or diploid set (which is expressed by 2n), has a chromosome, so the chromosomes pair in the embryo pair.
The lowest number of chromosomes are found in round worms (Ascaris univalens) only 1 pair (ie 2n = 2 and n = 1). On the other hand, the amoeba proteus chromosome number is 250 pairs (ie 2n = 500 and n = 250). Also-
Physical structure of chromosomes:
The chromosome is covered with a thin sheet called pellicle, which protects its inner organs.
Inside the pelican, the substances like thick jellies are called materia (matrix) or matrix (marix).
At the metaphase stage, chromosomes have been found to have two equal body type and shaped truncated fibers along chromosomal length in maternal cortex, which is known as chromatid. Each fiber is called ginomena separately. They are scratched like springs and the color is well dyed.
There are two more substrates arranged in spiral along the chromatid length, which are known as chromonemata (chromonema, singular chromonema). These are not sprayed like spring and the color is not well dyed as it is not clearly visible. The chromonomas can not be separated from the genome.
Each chromonema has two mutilated twisted fibers. If these fibers are easily separated from each other, then the paranormick coil (and if not easily separated), then it is called the Pleviacental coil.
Because chromonomata is coiled, along with its entire length, there are many genetic objects which occur in chromomerae.
Each chromosome has a circular stretch, which is called primary constriction or centromere. The side of the centromier is called the arm of chromosomes.
In addition to centromere in one or both arms of many chromosomes, another groove is found to be called secondary constriction. In the minor constraints that take part in nucleosol synthesis, they are called NOR, and Nuclear Organizer chromosomes are called nuclear chromosomes. The number of such chromosomes in each nucleus.
The posterior bloom of the chromosomal arm is called satelite. Satellite-prone chromosomes are called sat chromosomes.
The poles of the two arms of the chromosomes are called telomere, influenced and sensitive to the surface. Due to this quality, they are not associated with the fragmentation of other chromosomes.
Types of chromosomes:
Based on work, two types of chromosomes, such as autosome and sex or sex determination chromosomes.
The chromosomal controlling chromosomes in autosome and sexual properties that control the body properties are called sex chromosome.
There are 44 (22 pairs of autosomes) in the human body and two (1 pair) of sex or sex determination chromosomes, and 22 in autogenous genes (sperm or ova), and the number of sex or sex determination chromosomes 1.
Five types of chromosomes based on the shape, namely-
Differences in chromosomes can be seen in different stages of cell division. In the interface phase, chromosomes are sloppy, while on the other side, it is dumped in the prophase phase. The shape of the metaphase and anaphase is dependent on centromere position. For example,
Metrocentric chromosomes are in the middle of the centromere chromosome, so that both arms are equal or nearly the same, which is similar to the V character of English in the anaphase phase.
In the sub-metatricric chromosomes, the centromere chromosomes tend to be slightly side-to-side, so that both arms are uneven, which is similar to the L-letter in English in the anaphase phase.
Acroresentric chromosomes are located near the extremity of centromere chromosomes, so that both arms are too small and bigger, like the J-letter of English to look at the anaphase phase.
The telescopic chromosomes tend to be on the edge of the centromere chromosomes, and only one arm is seen in its chromosomes, which is similar to the English letter I see at the anaphase stage. Such chromosomes are rare.
Assentric chromosomes do not have centromere.