Question

Given above is a schematic break-up of the phases/stages of cell cycle. Which one of the following is the correct indication of the stage/phase in the cell cycle?

a. A - Cytokinesis
b. B - Metaphase
c. C - Karyokinesis
d. D - Synthetic Phase

Answer 1

The order of the process of cell cycle is such that the division of the cellular contents and the nucleus comes at the end of mitosis when the chromosomes have been separated up from their condensed form.

Complete answer:
The phases of the cell cycle are in the order of mitosis, G1 then synthetic phase and the followed by the G2 phase. There are also different phases in the mitosis which regulates the division of the chromosomes from the condensed state.

The first phase of the mitosis is the prophase where the spindle fibers start to appear for the first time and by the end of prophase the chromosomes start to condense. Then after prophase metaphase is there in which the chromosomes start aligning near the center of the cell. This is followed by the stage of anaphase in which the centromeres divide and the sister chromatids start to move near the opposite poles. The last stage of the mitosis is the telophase in which the chromosomes again start to condense up and the nuclear membrane reforms giving the shape like two cells and by the end the spindle fibers disappear.

After mitosis the cell undergoes the process of cytokinesis in which the cytoplasm is divided for the two new cells. Now the parent cells have become two new cells in which the genetic information of both the new cells is the same as the parent cell.

Then the cell slips up into the G1 phase where the cellular components and the organelles double up except for the chromosomes. Then this stage is followed by the Synthetic phase in which the chromosomes in the new cell get duplicated. Then the last stage which is required to happen in the cell cycle is the G2 phase where karyokinesis means division of cell nucleus takes place.

Hence, the correct answer is option (D).

Note: Cytokinesis is not the term for the entire four processes of mitosis rather it is a completely different step and karyokinesis is the last step of the entire cell cycle and not the mitosis. Cancer results due to uncontrolled cell division which is a manifestation of the change or defect in the activities of cell cycle regulators.