During anaphase of mitosis, how are chromosomes separated?

• A. Chromosomes are separated by the breakdown of the cytoskeleton.
• B. Chromosomes are separated by the nuclear envelope reforming around them.
• C. Chromosomes are pulled apart by spindle fibers attached to centromeres.
• D. Chromosomes are divided by the cell membrane pinching inwards.

Answer: (C)

Verified step by step guidance

1. Understand the context of mitosis: Mitosis is a process of cell division that results in two genetically identical daughter cells. It consists of several phases, including prophase, metaphase, anaphase, and telophase.
2. Focus on anaphase: During anaphase, the sister chromatids are separated and pulled towards opposite poles of the cell. This is a critical step in ensuring that each daughter cell receives an identical set of chromosomes.
3. Identify the role of spindle fibers: Spindle fibers are structures made of microtubules that form during cell division. They attach to the centromeres of chromosomes, which are the regions where sister chromatids are joined.
4. Explain the mechanism of separation: During anaphase, the spindle fibers shorten, pulling the sister chromatids apart. This is facilitated by motor proteins that move along the microtubules, effectively dragging the chromatids towards opposite ends of the cell.
5. Clarify the incorrect options: The breakdown of the cytoskeleton, nuclear envelope reforming, and cell membrane pinching are not involved in chromosome separation during anaphase. These processes occur at different stages or are part of other cellular functions.