Chromosome.
(1) Chromatid. One of the two copies of the chromosome after S phase.
(2) Centromere. A centromere is a region of DNA typically found near the middle of a Chromosome where two Sister chromatids come in contact The point where the two chromatids touch, and where the microtubules attach.
(3) Short arm
(4) Long arm.

A chromatid is one of two identical copies of DNA making up a chromosome, which are joined at their centromeres, for the process of cell division (mitosis or meiosis). A chromosome is an organized structure of DNA and Protein that is found in cells. A centromere is a region of DNA typically found near the middle of a Chromosome where two Sister chromatids come in contact Cell division is a process by which a cell, called the parent cell divides into two or more cells called daughter cells. Mitosis is the process in which a Eukaryotic cell separates the Chromosomes in its Cell nucleus, into two identical sets in two daughter nuclei In Biology or life science meiosis (pronounced my-oh-sis is a process of reductional division in which the number of chromosomes per cell is cut in half The term is used so long as the centromeres remain in contact. When they separate (during anaphase of mitosis and anaphase 2 of meiosis), the strands are called daughter-chromosomes. Anaphase, from the Ancient Greek ἀνά (up and φάσις (stage is the stage of Mitosis when Chromosomes

In other words, a chromatid is "one-half of a replicated chromosome". ^[1] It should not be confused with the ploidy of an organism, which is the number of homologous versions of a chromosome. "Haplo" redirects here For the fictional character see The Death Gate Cycle. Homologous chromosomes are Chromosomes in a Biological cell that pair ( synapse) during Meiosis, or alternatively non-identical chromosomes that

Quantity

In humans, for example, there are normally 23 pairs of homologous chromosomes in each cell (N=23). However, the quantity of chromatids will be a multiple of 23. It can be either 4N, 2N or 1N. The last is only seen in haploid gametes, with only one of each homologous chromosome pair. "Haplo" redirects here For the fictional character see The Death Gate Cycle. Such are created in gametogenesis. Gametogenesis is a process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid Gametes Depending on the Biological

4N

In a cell with 4N chromatids, there are 23 chromosome pairs (46 chromosomes), and each chromosome has 2 chromatids. Thus, there are 92 chromatids in each cell (4N). It occurs after the S phase of interphase. (See cell cycle). The cell cycle, or cell-division cycle, is the series of events that take place in a eukaryotic cell leading to its replication

2N

Immediately after a mitosis, where a cell has divided in two, but not yet duplicated its DNA in S phase, there are still 23 chromosome pairs (46 chromosomes). Mitosis is the process in which a Eukaryotic cell separates the Chromosomes in its Cell nucleus, into two identical sets in two daughter nuclei However, each chromosome only has one chromatid. Thus there are 46 chromatids (2xN)

Alternatively, a haploid cell with two chromatids per chromosome also has 46 chromatids. However, this doesn't occur naturally in humans.

1N

Immediately after meiosis, each cell, called a gamete, only has half the amount of chromosomes (23 chromosomes). In Biology or life science meiosis (pronounced my-oh-sis is a process of reductional division in which the number of chromosomes per cell is cut in half A gamete (from Ancient Greek γαμέτης; translated gamete = wife gametes = husband is a cell that fuses with another gamete Furthermore, each chromosome only has one chromatid. Thus, there are 23 chromatids (1xN)

Etymology

The term chromatid was proposed by Clarence Erwin McClung (1900) for each of the four threads making up a chromosome-pair during meiosis. Clarence Erwin McClung ( 5 Apr 1870 - 17 Jan 1946) was an American Biologist who discovered the role of Chromosomes A chromosome is an organized structure of DNA and Protein that is found in cells. In Biology or life science meiosis (pronounced my-oh-sis is a process of reductional division in which the number of chromosomes per cell is cut in half It was later used also for mitosis. Mitosis is the process in which a Eukaryotic cell separates the Chromosomes in its Cell nucleus, into two identical sets in two daughter nuclei

The term derives from the Greek chroma (colour); for the derivation of -id, see cytokinesis. Cytokinesis is the process whereby the Cytoplasm of a single Eukaryotic cell is divided to form two daughter cells

References

1. ^ Chromatid - A Cell Biology Definition