During which stage of the cell cycle do cells condense chromatin into chromosomes?

During prophase, the chromatin condenses into distinct chromosomes, which is a crucial step in the cell cycle. This process is necessary for the equal distribution of genetic material during cell division. As the nucleolus fades and the nuclear envelope begins to break down, the tightly coiled chromosomes become visible under a light microscope, typically appearing as sister chromatids joined at the centromere. This visibility is essential for later stages of mitosis, as it ensures that each daughter cell will receive an identical set of chromosomes when the cell divides.

In contrast, during metaphase, the chromosomes align at the cell's equatorial plane, while telophase marks the stage where the chromosomes begin to de-condense back into chromatin as the nuclear envelope reforms around each set of chromosomes, separating the nuclei of the two daughter cells. Interphase is the period when the cell is not dividing; instead, it is preparing for division by replicating its DNA and performing normal cellular functions.