SACE Stage 2 Biology Practice Exam

During prophase, the nucleolus undergoes significant changes as the cell prepares to divide. The correct answer indicates that the nucleolus disappears during this phase. This occurs because, as the cell enters prophase, the chromatin condenses into visible chromosomes, and the nuclear envelope begins to break down. The disappearance of the nucleolus is important for the overall process of cell division, as it reflects the transition of the cell from a non-dividing state (interphase) into a dividing state, where genetic material is organized and prepared for separation into daughter cells.

The nucleolus is responsible for ribosomal RNA synthesis and assembly of ribosomes, but during prophase, the focus shifts to the segregation of chromosomes. As a result, the nucleolus is no longer needed until after the cell has divided, when it will reappear during the later phases of mitosis as the cell returns to its interphase state.