Biology

Question

Why does the cell membrane pinch in during telophase of mitosis? What causes the actual action of the cell membrane dividing into two separate membranes around the daughter cells?

Answer

Hi Mary, The process of cytokinesis, the splitting of the cytoplasm and encapsulation within a new cell membrane following chromosomal segregation, is poorly understand. It appears that one or more "contractile rings" are formed around the body of the cell at its midpoint. At least one of the rings is compsoed of the proteins actin and myosin, the same proteins responsible for muscle contraction. It appears the rings contract and new membrane is added at the point of contraction until the two new daughter cells are "pinched off" at the constriction site. The exact role of the contraction rings and the regulation of new membrane formation are still poorly understood, and much reseacrh is looking at the parallel process in bacteria and yeasts. Hope this helps-Bob