Chromosome is the main component of heredity. The conversion of chromatin into the cell division transforms into a decaying structure in chromosomes, which contain all the properties of the organism , and through this the properties are transmitted to the progeny. Chromosomes contain deoxyribonucleic acids or DNA or genes and synthesize proteins through DNA . It is located in the nucleus.
Discover chromosomes
In 1888 , the scientist Waldeyer named the chromatin in the formation of the decaying structure found in the phase of cell division in chromosomes. In 1933 , the scientist Bovery proved that the chromosomes are the inheritors and carriers. In 1935 , the scientist Heitz first described the formation of chromosomes. In 1966 , the scientist Dupraw described the subtle structure of chromosomes.
Structure
Chromosomes in length 0.2 - 50 micron (μ) or micrometer (μm) and width is 0.2 micrometers (μ) or micrometer (μm). The length of human chromosomes is 6 micron (μ) or micrometer (μm).
Types of chromosomes
Based on work, two types of chromosomes, chromosomes controlling body properties, are called autosomes and chromosomes that control the sexual properties are called sexual chromosomes. Autosomes In the body the number 44 (two pair), and sexual orientation or gender determining chromosomes of the two (1 pair) and reproductive cells ( sperm or egg ) autosomes number twenty-two, and the number 1 sex or sex chromosomes.
At certain stages of cell division chromosome
Differences in chromosomes differ in different stages of cell division. At the interfase stage, the chromosomes are sloppy, while on the other side, it is dumped in the prophase stage. The shape of the metaphase and anaphase phase depends on centromere position. Metrocentric chromosomes are in the middle of the centromere chromosome, so that both arms are equal or nearly the same, in the anaphase phase, like the letter V in English. Sub-metacentric chromosomes tend to be slightly side of the centromere chromosomes, as both of its arms are incompatible, which are similar to the letters of English in the anaphase phase. Acroresentric chromosomes tend to be around the extremity of centromere chromosomes, so both of its arms are much smaller and larger, which look like the J-character in the anaphase phase. The teleosentric chromosomes are located on the edge of the centromere chromosome, as well as its chromosomes There is only one arm that looks like an I-letter in to see at the anaphase stage. Such chromosomes are rare. Assentric chromosomes do not have centromere.
The number of chromosomes
Chromosomes are specific to a particular species . In the same species, the genome (sperm and ova) of the genus is the number of chromosomes in the cell, which is half of the chromosomal number of the embryo, which is called the 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 chromosomes, 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, amoeba- proteus chromosomes are 250 pairs (ie 2n = 500 and n = 250).
Work chromosomes
The work of chromosomes is carried from the parents to the genetic offspring. Human eye color, hair type, skin structure etc. are carried out by chromosomes and maintain the genealogy pattern. Because of this, chromosomes are termed as "physical basis of heredity".