Prometaphase

Definition

Prometaphase is a stage of mitosis following prophase and preceding metaphase. During prometaphase, the nuclear envelope breaks down, allowing spindle fibers to attach to chromosomes at their kinetochores.

5 Must Know Facts For Your Next Test

1. The nuclear envelope disintegrates during prometaphase.
2. Spindle fibers extend from the centrosomes and attach to kinetochores on the chromosomes.
3. Chromosomes, now attached at their kinetochores, begin moving toward the cell's equatorial plane.
4. Kinetochores are protein structures that form on chromatids during cell division and are crucial for chromosome movement.
5. Prometaphase ensures that all chromosomes are properly attached to spindle fibers before progressing to metaphase.

Review Questions

Related terms

Prophase:

The first stage of mitosis where chromatin condenses into visible chromosomes and the mitotic spindle begins to form.

Metaphase:

The stage of mitosis where chromosomes align at the metaphase plate, or cell equator, ensuring proper segregation.

Kinetochores: Protein complexes on chromatids where spindle fibers attach during cell division to pull sister chromatids apart.