Florida Biology EOC Practice Test

During which stage of mitosis do sister chromatids line up in the middle of the cell?

1. Anaphase

2. Interphase

3. Metaphase

4. Prophase

The correct answer is: Metaphase

Sister chromatids line up in the middle of the cell during metaphase. This stage is essential for ensuring that each daughter cell receives an identical set of chromosomes. During metaphase, the chromosomes, which have already been duplicated during the previous stage of the cell cycle, are aligned along the metaphase plate (the equatorial plane of the cell). The microtubules of the spindle apparatus attach to the centromeres of the chromatids to prepare for their separation. This precise alignment is critical for the accuracy of chromosome segregation, reducing the risk of aneuploidy in the daughter cells. In contrast, anaphase is the stage where the sister chromatids are pulled apart toward opposite poles of the cell. Interphase is the stage that occurs before mitosis, during which the cell prepares for division, and prophase is when the chromatin condenses into visible chromosomes, and the nuclear envelope begins to break down.