Which structure is primarily responsible for separating sister chromatids during mitosis?

Which structure is primarily responsible for separating sister chromatids during mitosis?

• A. Centrosome
• B. Kinetochore
• C. Cleavage furrow
• D. Spindle fibers

Answer: (D)

During mitosis, the structure that is primarily responsible for separating sister chromatids is the spindle fibers. These fibers are composed of microtubules that extend from the centrosomes and attach to the kinetochores, which are protein complexes located at the centromeres of each chromatid. As the mitotic spindle becomes fully formed, the spindle fibers exert tension on the kinetochores, pulling the sister chromatids apart and moving them toward opposite poles of the dividing cell. This action is crucial for ensuring that each daughter cell receives an equal complement of chromosomes, maintaining genetic stability across cell generations. The role of spindle fibers is fundamental as they orchestrate this separation through dynamic destabilization and stabilization processes, which facilitate the movement of chromatids during anaphase. The other options, while important in various contexts of cell division, do not directly carry out the separation of sister chromatids. The centrosome serves as the organizing center for the microtubules but does not actively participate in the mechanics of separation. The kinetochore is essential for the attachment of chromosomes to the spindle fibers, but it is the spindle fibers that actually perform the movement. The cleavage furrow is involved in cytokinesis, the process of dividing the cytoplasm after

During mitosis, the structure that is primarily responsible for separating sister chromatids is the spindle fibers. These fibers are composed of microtubules that extend from the centrosomes and attach to the kinetochores, which are protein complexes located at the centromeres of each chromatid. As the mitotic spindle becomes fully formed, the spindle fibers exert tension on the kinetochores, pulling the sister chromatids apart and moving them toward opposite poles of the dividing cell.

This action is crucial for ensuring that each daughter cell receives an equal complement of chromosomes, maintaining genetic stability across cell generations. The role of spindle fibers is fundamental as they orchestrate this separation through dynamic destabilization and stabilization processes, which facilitate the movement of chromatids during anaphase.

The other options, while important in various contexts of cell division, do not directly carry out the separation of sister chromatids. The centrosome serves as the organizing center for the microtubules but does not actively participate in the mechanics of separation. The kinetochore is essential for the attachment of chromosomes to the spindle fibers, but it is the spindle fibers that actually perform the movement. The cleavage furrow is involved in cytokinesis, the process of dividing the cytoplasm after