What Happens During Metaphase In An Animal Cell

Stage of jail cell division

Metaphase in cells (here an animal cell) are characterized past the system of chromosomes at the equatorial plane of the spindle

Chromosomes lined up on the metaphase plate. 2 views with the metaphase plate rotated 60°.

Stages of early on mitosis in a vertebrate jail cell with micrographs of chromatids

Metaphase (from Ancient Greek μετα- (meta-) across, above, transcending [1] and [[φάσις (phásis) linguistic communication|φάσις (phásis)]] appearance) is a phase of mitosis in the eukaryotic cell cycle in which chromosomes are at their 2d-most condensed and coiled stage (they are at their almost condensed in anaphase).^[1] These chromosomes, carrying genetic information, align in the equator of the cell before being separated into each of the two daughter cells. Metaphase accounts for approximately iv% of the prison cell cycle's duration.^{[ commendation needed ]} Preceded by events in prometaphase and followed past anaphase, microtubules formed in prophase accept already found and attached themselves to kinetochores in metaphase.

In metaphase, the centromeres of the chromosomes convene themselves on the metaphase plate (or equatorial plate),^[ii] an imaginary line that is equidistant from the two centrosome poles. This even alignment is due to the weigh of the pulling powers generated by the opposing kinetochore microtubules,^[3] analogous to a tug-of-war between two people of equal force, ending with the destruction of B cyclin.^[four] In sure types of cells, chromosomes do not line up at the metaphase plate and instead motility back and along betwixt the poles randomly, only roughly lining up along the middleline.^{[ citation needed ]} Early events of metaphase can coincide with the later events of prometaphase, as chromosomes with connected kinetochores volition start the events of metaphase individually before other chromosomes with unconnected kinetochores that are notwithstanding lingering in the events of prometaphase.^{[ citation needed ]}

One of the jail cell cycle checkpoints occurs during prometaphase and metaphase. Just afterward all chromosomes have get aligned at the metaphase plate, when every kinetochore is properly fastened to a bundle of microtubules, does the prison cell enter anaphase. It is idea that unattached or improperly fastened kinetochores generate a signal to prevent premature progression to anaphase, fifty-fifty if most of kinetochores have been fastened and nearly of the chromosomes accept been aligned. Such a signal creates the mitotic spindle checkpoint. This would be accomplished by regulation of the anaphase-promoting complex, securin, and separase.

Metaphase in cytogenetics and cancer studies [edit]

Human metaphase chromosomes (normal male karyotype)

The assay of metaphase chromosomes is 1 of the main tools of classical cytogenetics and cancer studies. Chromosomes are condensed (thickened) and highly coiled in metaphase, which makes them virtually suitable for visual assay. Metaphase chromosomes make the classical picture of chromosomes (karyotype). For classical cytogenetic analyses, cells are grown in short term civilization and arrested in metaphase using mitotic inhibitor. Further they are used for slide preparation and banding (staining) of chromosomes to be visualised nether microscope to study structure and number of chromosomes (karyotype). Staining of the slides, often with Giemsa (Grand banding) or Quinacrine, produces a pattern of in total up to several hundred bands. Normal metaphase spreads are used in methods similar FISH and as a hybridization matrix for comparative genomic hybridization (CGH) experiments.

Malignant cells from solid tumors or leukemia samples can likewise be used for cytogenetic assay to generate metaphase preparations. Inspection of the stained metaphase chromosomes allows the determination of numerical and structural changes in the tumor cell genome, for example, losses of chromosomal segments or translocations, which may lead to chimeric oncogenes, such as bcr-abl in chronic myelogenous leukemia.

References [edit]

^ "Chromosome condensation through mitosis". ScienceDaily . Retrieved 12 June 2007.
^ "Metaphase plate". Biology Dictionary. Biology Online. Retrieved 9 December 2012.
^ "Metaphase". Nature Pedagogy. Retrieved 9 December 2012.
^ "The Cell Cycle". Kimball's Biology Pages. Archived from the original on 19 Nov 2012. Retrieved 9 December 2012.