During mitosis, where do microtubules attach to sister chromatids?

• A. At the spindle poles
• B. At the kinetochores
• C. At the nuclear envelope
• D. At the centrosomes

Answer: (B)

Verified step by step guidance

1. Understand the context of the question: Mitosis is a process of cell division where replicated chromosomes are separated into two daughter cells. Microtubules play a critical role in this process by attaching to specific structures on the chromosomes.
2. Identify the key term in the question: The term 'sister chromatids' refers to the identical copies of a chromosome that are connected by a centromere after DNA replication.
3. Recall the role of kinetochores: Kinetochores are protein complexes located at the centromere of each sister chromatid. They serve as the attachment points for spindle microtubules during mitosis.
4. Understand the function of microtubules: Microtubules are part of the mitotic spindle, which is responsible for pulling sister chromatids apart. They attach to the kinetochores to exert the forces needed for chromatid separation.
5. Conclude that microtubules attach to sister chromatids at the kinetochores, as this is the specific structure designed for this purpose during mitosis.