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10.5: Interfase
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10.5: Interphase

10.5: Interfase

The cell cycle occurs over approximately 24 hours (in a typical human cell) and in two distinct stages: interphase, which includes three phases of the cell cycle (G1, S, and G2), and mitosis (M). During interphase, which takes up about 95 percent of the duration of the eukaryotic cell cycle, cells grow and replicate their DNA in preparation for mitosis.

Phases of Interphase

Following each period of mitosis and cytokinesis, eukaryotic cells enter interphase, during which they grow and replicate their DNA in preparation for the next mitotic division.

During the G1 (gap 1) phase, cells grow continuously and prepare for DNA replication. During this phase, cells are metabolically active and copy essential organelles and biochemical molecules, such as proteins.

In the subsequent S (synthesis) phase of interphase, cells duplicate their nuclear DNA, which remains packaged in semi-condensed chromatin. During the S phase, cells also duplicate the centrosome, a microtubule-organizing structure that forms the mitotic spindle apparatus. The mitotic spindle separates chromosomes during mitosis.

In the G2 (gap 2) phase, which follows DNA synthesis, cells continue to grow and synthesize proteins and organelles to prepare for mitosis.

In human cells, the G1 phase spans approximately 11 hours, the S phase takes about 8 hours, and the G2 phase lasts about 4 hours. During G1, cells are diploid (2n, a pair of each chromosome). Following replication in S phase, cells increase their DNA content to 4n. Cells remain 4n until cytokinesis, at which point their DNA content is reduced to 2n.

El ciclo celular se produce durante aproximadamente 24 horas (en una célula humana típica) y en dos etapas distintas: interfase, que incluye tres fases del ciclo celular (G1,S y G2),y mitosis (M). Durante la interfase, que ocupa alrededor del 95 por ciento de la duración del ciclo celular eucariota, las células crecen y replican su ADN en preparación para la mitosis.

Fases de la interfase

Después de cada período de mitosis y citoquinesis, las células eucariotas entran en la interfase, durante el cual crecen y replican su ADN en preparación para la siguiente división mitótica.

Durante la fase G1 (brecha 1), las células crecen continuamente y se preparan para la replicación del ADN. Durante esta fase, las células son metabólicamente activas y copian orgánulos esenciales y moléculas bioquímicas, como proteínas.

En la fase S (síntesis) posterior de la interfase, las células duplican su ADN nuclear, que permanece empaquetado en cromatina semicons condensada. Durante la fase S, las células también duplican el centrooma, una estructura organizadora de microtúbulos que forma el aparato del husillo mitótico. El husillo mitótico separa los cromosomas durante la mitosis.

En la fase G2 (brecha 2), que sigue la síntesis de ADN, las células continúan creciendo y sintetizando proteínas y orgánulos para prepararse para la mitosis.

En las células humanas, la fase G1 abarca aproximadamente 11 horas, la fase S tarda aproximadamente 8 horas y la fase G2 dura aproximadamente 4 horas. Durante G1,las células son diploide (2n, un par de cada cromosoma). Después de la replicación en la fase S, las células aumentan su contenido de ADN a 4n. Las células permanecen 4n hasta que la citoquinesis, momento en el que su contenido de ADN se reduce a 2n.


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