The article discusses research being done on cell cycle. It references the study"Structure of the mitotic checkpoint complex," by W. C. H. Chao in the same issue of the journal. It says that SAC ensures chromosome segregation during mitosis through anaphase blockage. It adds that spindle assembly checkpoint SAC is inserted by the mitotic checkpoint complex (MCC) that inhibits the anaphase-promoting complex (APC) and detects the unattached chromosomes.