Which of the following is NOT related to prophase of mitosis?

During prophase of mitosis, the initial events set the stage for chromosomal arrangement and separation. One key feature of prophase is the condensation of chromatin into visible chromosomes, making them easier to observe under a microscope. As the chromatin condenses, the individual sister chromatids become distinguishable.

The nucleolus typically disappears during this stage, and the nuclear envelope begins to break down, allowing for the microtubules that will later form the mitotic spindle to reach the chromosomes. This overall transition prepares the cell for the subsequent phases of mitosis.

While spindle microtubules are indeed critical for chromosome movement, their attachment to the centromeres of chromosomes generally occurs in the next phase, metaphase. Prophase primarily involves chromatin condensation and the preparation for spindle attachment but does not feature direct attachment of spindle microtubules at centromeres.

Therefore, the option related to spindle microtubules attaching to the centromere is not characteristic of prophase, as this process is more accurately described during metaphase.