Question

Why eliminate cyclins and transcription factors once they are no longer needed?

Answer 1

It is necesary to inhibit the cyclins or transcription factors so inorder to prevent the unnecessary cell division or gene expression respectively.

As cyclins build up activates cdk and cdk-cyvclins helps in the progression of cell cycle.The unregulated cell cycle can cause uncontrol cellular proliferation and which may lead to process of tumour formation or cancer.Hence inorder to prevent this the cyclins need to be stopped or degraded after succesfull cell cycle completion.

The transcription factors intiates gene expression so in order to prevent the unnecessary gene expression which wastes cellular energy and may leads to undesirable concentartion of gene products which can be toxic.It can also lead to activation of various genes taht can control cell division.Hence again causing the tumour formations.So transcriptions factors also needed to be degraded.