Where does spindle fibres attach to during metaphase?

The correct answer is kinetochore of the chromosome.

Step-by-Step Explanation:

1. Understanding the Centromere vs. Kinetochore:
Every eukaryotic chromosome has a constricted region called the centromere, which holds sister chromatids together. During cell division (mitosis and meiosis), a specialized, proteinaceous disc-shaped structure called the kinetochore assembles on the outer surface of this centromere.

2. Role of Spindle Fibres:
Spindle fibres are composed of microtubules radiating from the centrosomes (spindle poles). The primary function of these microtubules during cell division is to attach to chromosomes and align them along the metaphase plate, and subsequently pull sister chromatids apart during anaphase.

3. Physical Attachment:
Rather than binding directly to the DNA of the centromere itself, the microtubules of the spindle fibres specifically bind to the protein complexes that make up the kinetochore. This attachment provides the physical link necessary for the spindle apparatus to exert pulling forces on the chromosomes.

4. Conclusion:
Therefore, during metaphase, spindle fibres attach specifically to the kinetochore of the chromosome.