During mitosis, what cellular structure is primarily responsible for moving chromosomes to opposite poles of the cell?

• A. Intermediate filaments of the nuclear lamina
• B. The actin-rich contractile ring
• C. The mitotic spindle (spindle microtubules)
• D. The smooth endoplasmic reticulum

Answer: (C)

Verified step by step guidance

1. Identify the key cellular structures involved in mitosis that can influence chromosome movement.
2. Understand the role of intermediate filaments of the nuclear lamina, which mainly provide structural support to the nucleus but do not move chromosomes.
3. Recognize that the actin-rich contractile ring functions during cytokinesis to divide the cell, not to move chromosomes.
4. Focus on the mitotic spindle, composed of spindle microtubules, which attach to chromosomes and pull them toward opposite poles during mitosis.
5. Note that the smooth endoplasmic reticulum is involved in lipid synthesis and detoxification, not chromosome movement.