Prophase


Prophase

Prophase, from the ancient Greek πρό (before) and φάσις (stage), is a stage of mitosis in which the chromatin condenses (it becomes shorter and fatter) into a highly ordered structure called a chromosome in which the chromatin becomes visible. This process, called chromatin condensation, is mediated by the condensin complex. Since the genetic material has been duplicated in an earlier phase of the cell cycle, there are two identical copies of each chromosome in the cell. Identical chromosomes, called sister chromatids, are attached to each other at a DNA element present on every chromosome called the centromere. During prophase, giemsa staining can be applied to elicit G-banding in chromosomes. Prophase accounts for approximately 3% of the cell cycle's duration.

An important organelle in mitosis is the centrosome, the microtubule organizing center in metazoans. During prophase, the two centrosomes, which replicate independently of mitosis, have their microtubule-activity increased due to the recruitment of γ-tubulin. The centrosomes will be pushed apart to opposite ends of the cell nucleus by the action of molecular motors acting on the microtubules. The nuclear envelope breaks down to allow the microtubules to reach the kinetochores on the chromosomes, marking the end of prophase. Prometaphase, the next step of mitosis, will see the chromosome being captured by the microtubules.


| chapter = Section 1. The Biology of the Plant Cell – 3. The Plant Cell and the Cell Cycle | pages = 58–67 | isbn = 978-0-7167-1007-3 | oclc = 56051064 | id = LCCN 2004-053303 | url = http://books.google.com/?id=8tz2aB1-jb4C&pg=PA58

| year = 2005 }}</ref>

References

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  • prophase — [ profaz ] n. f. • 1887; de pro et phase ♦ Biol. Première phase de la division cellulaire (méiose ou mitose) où les chromosomes s individualisent en filaments fissurés longitudinalement, et se disposent par paires de chromosomes homologues. ●… …   Encyclopédie Universelle

  • prophase — 1884, from Ger. prophase (1884); see PRO (Cf. pro ) + PHASE (Cf. phase) …   Etymology dictionary

  • prophase — prophase. См. профаза. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • Prophase — Prophase, 1. Phase der ⇒ Mitose und der ⇒ Meiose …   Deutsch wörterbuch der biologie

  • prophase — [prō′fāz΄] n. [ PRO 1 + PHASE1] the first stage in mitosis, during which the chromatin is formed into chromosomes which split into separate paired chromatids …   English World dictionary

  • Prophase — Schematische Darstellung der Mitose I: Interphase; II: Prophase; III: Prometaphase; IV: Metaphase; V und VI: Anaphase; VII: Telophase; VIII: Zytokinese Als Mitose (zu griechisch μίτος = Faden) (auch Karyokinese) bezeichnet man den Vorgang der …   Deutsch Wikipedia

  • Prophase — La prophase est la première phase de la division cellulaire (mitotique comme méiotique) chez les êtres vivants eucaryotes. Lors de cette phase, le matériel génétique (ADN), qui en temps normal est présent dans le noyau sous la forme de chromatine …   Wikipédia en Français

  • prophase — The first stage of mitosis or meiosis, consisting of linear contraction and increase in thickness of the chromosomes (each composed of two chromatids) accompanied by migration of the two daughter centrioles and their asters toward the poles of… …   Medical dictionary

  • Prophase — Pro|pha|se 〈f. 19〉 einleitende Phase der Kernteilung, in der die Chromosomen sichtbar werden [<lat. pro „vor, vorher“ + Phase] * * * Pro|pha|se, die [aus griech. pró = vor u. ↑ Phase] (Biol.): erste Phase der indirekten Kernteilung. * * *… …   Universal-Lexikon

  • prophase — n. the first stage of mitosis and of each division of meiosis, in which the chromosomes become visible under the microscope. The first prophase of meiosis ocurs in five stages (see leptotene, zygotene, pachytene, diplotene, diakinesis) …   The new mediacal dictionary


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