Metaphase

Metaphase is a stage of mitosis in the eukaryotic cell cycle in which chromosomes are at their second-most condensed and coiled stage. This stage takes place after prophase and prometaphase, and is followed by anaphase and telophase.

Overview

During metaphase, the cell nucleus disappears and chromosomes align themselves along the metaphase plate (or equatorial plane), an imaginary line that is equidistant from the two centrosomes at the opposite ends of the cell. The paired chromosomes are said to be in a state of high tension, due to the action of microtubules pulling in opposite directions.

Metaphase in Mitosis and Meiosis

In mitosis, metaphase is preceded by prophase and prometaphase. During these stages, the chromosomes condense and the mitotic spindle forms to separate them. In meiosis, metaphase occurs in both meiosis I and meiosis II.

Metaphase Checkpoint

The metaphase checkpoint, also known as the spindle checkpoint, is a safety mechanism that ensures the proper segregation of chromosomes during cell division. If a chromosome is not properly attached to the mitotic spindle, the checkpoint is activated and cell division is halted.

Metaphase in Medical Science

In medical science, metaphase is often used in karyotyping, a method used to identify and evaluate the size, shape, and number of chromosomes in a sample of body cells. This technique is often used in prenatal diagnosis and in the diagnosis of genetic disorders.

See Also

• Cell cycle
• Mitosis
• Meiosis
• Karyotype

Metaphase

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  Spindle chromosomes
• Metaphase chromosomes
  Metaphase chromosomes
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  Stages of early mitosis in a vertebrate cell with micrographs of chromatids
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  NHGRI human male karyotype