Metaphase I: Homologous chromosome pairs align at metaphase plate. Which statement is correct?

• A. The duplicated chromosomes move to the center of the cell.
• B. Sister chromatids separate.
• C. Homologue pairs line up at the metaphase plate.
• D. The nucleus disappears.

Answer: (C)

During metaphase I of meiosis, homologous chromosome pairs align at the metaphase plate. Each chromosome is made of two sister chromatids, but it is the paired homologs that line up together so that, when they separate in anaphase I, one member of each pair is pulled to each pole. The sister chromatids stay attached at their centromeres through metaphase I, only separating later in meiosis II. The nuclear envelope has already broken down earlier, so metaphase I isn’t defined by a visible nucleus. This arrangement of homologous pairs at the plate is the characteristic feature of metaphase I.