Metafázislemez

Metafázislemez, also known as the equatorial plate, is a temporary structure formed during cell division, specifically during metaphase of mitosis and meiosis. It is an imaginary plane equidistant from the two poles of the spindle apparatus. Chromosomes, each consisting of two sister chromatids, align along this plane.

The formation of the metafázislemez is a crucial step ensuring that each daughter cell receives an identical set of chromosomes. During prometaphase, spindle fibers attach to the kinetochores of each chromosome. These fibers then exert forces, pulling and pushing the chromosomes until they are all positioned at the center of the cell, forming the metafázislemez. This precise alignment is critical for the subsequent separation of sister chromatids in anaphase.

The metafázislemez is dynamic, meaning the chromosomes are not rigidly fixed but are constantly moving back and forth along the plate until the cell commits to proceeding to anaphase. This ensures that the tension from opposing spindle fibers is balanced on each sister chromatid. Once aligned, the cell receives the signal to degrade proteins that hold sister chromatids together, allowing them to be pulled to opposite poles. The term "metafázislemez" is derived from the Greek words "meta" (between) and "phasis" (stage), referring to its position during the metaphase stage of cell division.