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In this diagram of a duplicated chromosome, (2) identifies the centromere—the region that joins the two sister chromatids, or each half of the chromosome. In prophase of mitosis, specialized regions on centromeres called kinetochores attach chromosomes to spindle fibers. The centromere links a pair of sister chromatids together during cell ...
The largest regions on each chromosome are the short arm p and the long arm q, separated by a narrow region near the center called the centromere. [1] Other specific regions have also been defined, some of which are similarly found on every chromosome, while others are only present in certain chromosomes. Named regions include: Arms (p and q ...
Chromosome 15 is one of the 23 pairs of chromosomes in humans.People normally have two copies of this chromosome. Chromosome 15 spans about 99.7 million base pairs (the building material of DNA) and represents between 3% and 3.5% of the total DNA in cells.
3D rendering of centrioles showing the triplets. In cell biology a centriole is a cylindrical organelle composed mainly of a protein called tubulin. [1] Centrioles are found in most eukaryotic cells, but are not present in conifers (), flowering plants (angiosperms) and most fungi, and are only present in the male gametes of charophytes, bryophytes, seedless vascular plants, cycads, and Ginkgo.
Centromere placement on the chromosome can be characterized by four main arrangements, either metacentric, submetacentric, acrocentric, or telocentric. Both of these properties (i.e., the length of chromosomal arms, and the placement of the chromosomal centromere) are the main factors for creating structural homology between chromosomes.
In addition to the centromere, one or more secondary constrictions can be observed in some chromosomes at metaphase. In humans they are usually associated with the short arm of an acrocentric chromosome, [1] such as in the chromosomes 13, 14, 15, 21, & 22.
[3] [4] Although the centrosome has a key role in efficient mitosis in animal cells, it is not essential in certain fly and flatworm species. [5] [6] [7] Centrosomes are composed of two centrioles arranged at right angles to each other, and surrounded by a dense, highly structured [8] mass of protein termed the pericentriolar material (PCM).
A karyogram or idiogram is a graphical depiction of a karyotype, wherein chromosomes are generally organized in pairs, ordered by size and position of centromere for chromosomes of the same size. Karyotyping generally combines light microscopy and photography in the metaphase of the cell cycle , and results in a photomicrographic (or simply ...