prophase

American Heritage Dictionary:

pro·phase

(prō'fāz') pronunciation

The first stage of mitosis, during which the chromosomes condense and become visible, the nuclear membrane breaks down, and the spindle apparatus forms at opposite poles of the cell.
The first stage of meiosis, constituted by a series of events that include the thickening and coiling of the chromosomes, synapsis of homologous chromosomes, tetrad formation, and crossing over.

prophasic pro·pha'sic (-fā'zĭk) adj.

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prophase

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the initial stage of mitosis or meiosis in which the chromosomes are condensed, becoming apparent within the nucleus, but are not yet attached to a mitotic spindle. By early prophase, the single centrosome contains two centriole pairs; at late prophase, the centrosome divides and the two asters move apart. In meiosis, the chromosomes come together in homologous pairs, and undergo crossing-over. This occurs during the first of the two meiotic cell divisions, and is divided into several stages. In the first, zygotene, a complex structure develops between the two sister chromatids of each pair, which may play a part in recombination. They remain in the complex during a stage known as pachytene, then separate at the diplotene stage.

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Saunders Veterinary Dictionary:

prophase

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The first stage of cell replication in either meiosis or mitosis.

Random House Word Menu:

categories related to 'prophase'

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Random House Word Menu by Stephen Glazier

For a list of words related to prophase, see:

Genetics, Heredity, and Evolution - prophase: early stage in nuclear division during which chromosomes move toward equator of spindle

Wikipedia on Answers.com:

Prophase

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Prophase, from the ancient Greek πρό (before) and φάσις (stage), is a stage of mitosis in which the chromatin coils into double rod-shaped structures called chromosomes in which the chromatin becomes visible. This process, called chromatin condensation, is mediated by the condensin complex. Since the genetic material has been earlier phase of the cell cycle, there are two identical copies of each chromosome in the cell, called homologous chromosomes. Identical chromosomes, called sister chromatids, are attached to each other at a DNA element present on every chromosome called the centromere. Also during prophase, giemsa staining can be applied to elicit G-banding in chromosomes. Also, once the chromosomes form, the nucleolus fades. 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.

Basically, the chromatin in the nucleus coils into chromosomes. The nucleolus disintegrates and the centrosomes move to opposite poles of the cell, forming a bridge of spindle fibers.

In metaphase, the next step of mitosis, the nuclear membrane falls apart and the chromosomes are captured by the microtubules.

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References

^ "Biology of plants". 2005. pp. 58–67. ISBN 978-0-7167-1007-3. OCLC 56051064. LCCN 2004-053303. http://books.google.com/?id=8tz2aB1-jb4C&pg=PA58.

External links

Prophase at Online Biology Dictionary

Wikimedia Commons has media related to: Prophase

Cell cycle proteins

Cyclin

A (A1, A2) · B (B1, B2, B3) · D (D1, D2, D3) · E (E1, E2)

CDK

2 · 3 · 4 · 5 · 6 · 7 · 8 · 9 · 10 · CDK-activating kinase

CDK inhibitor

INK4a/ARF (p14arf/p16, p15, p18, p19) · cip/kip (p21, p27, p57)

P53 p63 p73 family

p53 · p63 · p73

Phases and
checkpoints

Interphase	G₁ phase · S phase · G₂ phase

M phase	Mitosis (Preprophase · Prophase · Prometaphase · Metaphase · Anaphase · Telophase) · Cytokinesis

Cell cycle checkpoints	Restriction point · Spindle checkpoint · Postreplication checkpoint

Other cellular phases	Apoptosis · G₀ phase · Meiosis

B bsyn: dna (repl, cycl, reco, repr) · tscr (fact, tcrg, nucl, rnat, rept, ptts) · tltn (risu, pttl, nexn) · dnab, rnab/runp · stru (domn, 1°, 2°, 3°, 4°)

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

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Translations:

Prophase

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Dansk (Danish)
n. - profase

Nederlands (Dutch)
eerste fase in de celdeling

Français (French)
n. - prophase

Deutsch (German)
n. - Prophase (Stadium in der Zellteilung)

Ελληνική (Greek)
n. - πρόφαση (πρώτη φάση της πυρηνικής διαίρεσης)

Italiano (Italian)
profase

Português (Portuguese)
n. - prófase (f) (Biol.)

Русский (Russian)
профаза

Español (Spanish)
n. - profase

Svenska (Swedish)
n. - förstadium, profas (biol.)

中文（简体）(Chinese (Simplified))
前期

中文（繁體）(Chinese (Traditional))
n. - 前期

한국어 (Korean)
n. - (유사분열의) 전기

日本語 (Japanese)
n. - 前期

العربيه (Arabic)
‏(الاسم) الطور الأول في انقسام الخليه‏

עברית (Hebrew)
n. - ‮השלב הראשון בחלוקת תאי הצמח או החי - התכווצות כרומוזומים‬

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Related answers:

	Which of the following is a characteristic seen in prophase you that does not occur in prophase II? Read answer...
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	How does prophase 1 differ from prophase 2?
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Copyrights:

		American Heritage Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved. Read more
		Oxford Dictionary of Biochemistry. Oxford University Press. Oxford Dictionary of Biochemistry and Molecular Biology © 1997, 2000, 2006 All rights reserved. Read more
		Saunders Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved. Read more
		Random House Word Menu. © 2010 Write Brothers Inc. Word Menu is a registered trademark of the Estate of Stephen Glazier. Write Brothers Inc. All rights reserved. Read more
		Wikipedia on Answers.com. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article Prophase. Read more
		Translations. Copyright © 2007, WizCom Technologies Ltd. All rights reserved. Read more