Question

Cancer can be attributed to loss of control over the cell cycle. Briefly explain how a car losing its brakes is a good analogy to describe the loss of protein checkpoints of the cell cycle.

Answer 1

There are 3 main check points in cell cycle. G1 check point, G2 check point and M check point. In G1 check point, the integrity of the DNA tested. G2 check point is for testing if the DNA replication has occurred without any errors. M- check point is for determining proper attachment of spindle fibers to kinetochore of the chromosomes. If all the events of the cell cycle have undergone properly , cell cycle will continue. Any DNA damage can lead to cancer too. That is why the integrity of the DNA also tested in G1 phase of the cell cycle. These check points are like breaks in the car. They will see to that cell with no abnormality will proceed through the cell cycle. The check points will check the speed of cell cycle.

DNA changes are the important reason for cancer. If such a cell with DNA errors proceeds in to cell cycle it may resut in rapid cell division and cancer.

In a car, breaks control the speed of the car movement. If the breaks fail, the car will be controllable. So it is same as the check points that occur in the cell cycle.