Mitosis: Anaphase
At anaphase (Fig. 6) the chromatids making up each chromosome are pulled apart and begin to move away from each other under the control of the spindle fibers. Once they are pulled apart, the chromatids are now considered individual chromosomes. As anaphase progresses, the chromosomes on each end of the cell are pulled into a bundle. When they stop moving, telophase begins.
Figure 6. Anaphase of mitosis. In this phase, spindle fibers separate the sister chromatids to opposite sides of the cell. Image by M. Hanneman, 2021. CC BY-NC-SA 4.0.