In Eukaryotic Cells,which Occurs During the Prophase of Mitosis

Question

In eukaryotic cells,which occurs during the prophase of mitosis?  
A) Duplication of chromatids
B) Replication of DNA
C) Separation of sister chromatids
D) Breakup of the nuclear envelope
E) Appearance of the nuclear envelope

Accepted Answer

During prophase of mitosis, the nuclear envelope breaks down, allowing the chromosomes to condense and attach to the spindle fibers. This is necessary for proper segregation of chromosomes during cell division. Duplication of chromatids and replication of DNA occur before prophase during S phase of the cell cycle, while separation of sister chromatids occurs during anaphase. The appearance of the nuclear envelope occurs after the completion of mitosis during telophase.