What Is the Shortest Stage in Mitosis? (Fastest Phase Explained)

The shortest stage in mitosis is anaphase. While cytokinesis follows mitosis and is brief, it is not part of mitosis itself but a separate process that divides the cytoplasm. Among the four phases of mitosis—prophase, metaphase, anaphase, and telophase—anaphase is consistently the fastest, typically lasting only a few minutes.

Anaphase begins abruptly after the metaphase checkpoint confirms that chromosomes are properly attached to spindle fibers. At this point, cohesin proteins holding sister chromatids together are cleaved by the enzyme separase. Once these connections break, the chromosomes are pulled toward opposite poles of the cell by shortening microtubules. This movement is rapid and efficient, driven by the depolymerization of spindle fibers at a controlled rate. Because no further preparation is needed after the checkpoint, the phase proceeds quickly and ends just as fast.

In a typical human cell, mitosis lasts about 90 minutes, with anaphase accounting for roughly 4 to 5 minutes. In faster-dividing cells, such as those in animal embryos, it may last as little as 2 to 3 minutes Khan Academy. This brevity reflects the mechanical precision of the process: chromosomes are already aligned and under tension, so their separation is nearly simultaneous. The speed helps reduce the window for errors, supporting accurate distribution of genetic material.

An example can be seen in onion root tip cells, commonly used in biology education. In these plant cells, the full mitotic process takes around 80 minutes, with anaphase occupying only 3 to 5 minutes. Prophase and metaphase take significantly longer due to tasks like chromatin condensation and spindle alignment, which require more time and regulatory steps. Anaphase, in contrast, executes a single, focused task—chromosome separation—without intermediate stages.

The duration of anaphase varies slightly across species and cell types. In yeast, it may last under a minute; in some mammalian cells, up to 10 minutes. Despite these small differences, anaphase remains the shortest mitotic phase across organisms, a sign of its evolutionary refinement.

Key Takeaways

• Anaphase is the shortest stage of mitosis, usually lasting only a few minutes.
• It involves the rapid separation of sister chromatids to opposite poles of the cell.
• Cytokinesis is brief but is not part of mitosis; it follows nuclear division.
• The speed and precision of anaphase help ensure accurate chromosome distribution Khan Academy.