Optometry Admission Test (OAT) Practice

In what stage of meiosis do sister chromatids line up at the equatorial plane?

1. Prophase I

2. Metaphase II

3. Metaphase I

4. Anaphase I

The correct answer is: Metaphase II

Sister chromatids line up at the equatorial plane during Metaphase II of meiosis. This stage is characterized by the alignment of the chromosomes in such a way that they are positioned along the metaphase plate, allowing for proper separation in the following phase, Anaphase II. Each chromosome is composed of two sister chromatids that were previously replicated during the S phase of the cell cycle. In metaphase II, the paired sister chromatids are attached to spindle fibers from opposite poles of the cell. This arrangement is crucial for ensuring that each daughter cell receives one copy of each chromosome when the sister chromatids are pulled apart in Anaphase II. The precision of this alignment helps maintain genetic stability across generations of cells, making it an integral part of the meiotic process. Other stages of meiosis involve different arrangements of chromosomes. For instance, in Prophase I, homologous chromosomes undergo recombination and are not yet aligned at the equatorial plane. In Metaphase I, homologous pairs are lined up rather than individual sister chromatids. Anaphase I involves the separation of homologous chromosomes, rather than sister chromatids. Therefore, Metaphase II is the only stage where sister chromatids are aligned along the equ