Fully formed spindles align homologous pairs of chromosomes on the metaphase plate during which stage of meiosis?

• A. Metaphase I
• B. Anaphase I
• C. Prophase I
• D. Metaphase II

Answer: (A)

Verified step by step guidance

1. Recall the stages of meiosis and their key events: Prophase I involves pairing of homologous chromosomes, Metaphase I involves alignment of homologous pairs on the metaphase plate, Anaphase I involves separation of homologous chromosomes, and Metaphase II involves alignment of sister chromatids.
2. Understand that the spindle apparatus is responsible for moving chromosomes during cell division and that fully formed spindles are necessary for chromosome alignment.
3. Identify that the alignment of homologous pairs (tetrads) on the metaphase plate occurs specifically during Metaphase I, distinguishing it from Metaphase II where sister chromatids align individually.
4. Recognize that Prophase I is when homologous chromosomes pair and crossing over occurs, but alignment on the metaphase plate happens later, in Metaphase I.
5. Conclude that the stage where fully formed spindles align homologous pairs on the metaphase plate is Metaphase I.