AP BIOLOGY

Detailed explanation-1: -During prophase, the chromosomes condense, the nucleolus disappears, and the nuclear envelope breaks down.

Detailed explanation-2: -At the end of prophase I, the nuclear membrane breaks down, the centrosomes have migrated to the opposite ends of the cell, and the spindle apparatus is being formed. This is followed by metaphase I. During this stage, the spindle fibers, or microtubules, attach to the centromere of each chromosome.

Detailed explanation-3: -Nuclear membrane disappears in late prophase. Longest phase of mitosis is prophase. During prophase, which occurs after G2 interphase, the cell prepares to divide by tightly condensing its chromosomes and initiating mitotic spindle formation.

Detailed explanation-4: -The nuclear membrane gets disappeared in the prophase itself and does not remain intact up to metaphase. It reappears in the telophase during mitosis.