What enables the copied chromosomes to separate during binary fission?
1: The septum splits the replicated chromosomes.
2: The nuclear membrane dissolves.
3: The mitotic spindle drives the separation.
4: The chromosomes are attached to different parts of cell membrane, which elongates and thus separates the chromosomes.
Answer: 3: The mitotic spindle drives the separation.
During binary fission, which is the asexual reproduction way in prokaryote organisms (e.g. bacteria), the division of chromosomes, which are duplicated in specific centers, occurs with the help of mitotic spindle. During mitosis, the spindle fiber is constructed by microtubules, which serves the function of the spindle. It binds to the chromosomes at kinetochore points that are created by it as the replication begins. Tensile stress that is implemented by the shortening spindle fibres is responsible for creating a pulling force which separates duplicated chromosomes and allows them to move towards opposite cell poles. This movement makes the organism that divides to have a complete set of chromosomes for each daughter cell remaining unsplitted. The mitotic spindle conducts the indispensable task of exact division of genetic material during the processes of binary fission as well as other forms of cell division.