Restriction Point
There is a "restriction point" present at the end of G1 phase. This point is a series of safeguards to ensure the DNA is intact and that the cell is functioning normally. Functionally, the safeguards exist as proteins known as cyclin-dependent kinases (CDK). The G1 CDK proteins activate the transcription factors for a variety of genes.These include genes which are responsible for DNA synthesis proteins and S phase CDK proteins.
Read more about this topic: G1 Phase
Famous quotes containing the words restriction and/or point:
“If we can find a principle to guide us in the handling of the child between nine and eighteen months, we can see that we need to allow enough opportunity for handling and investigation of objects to further intellectual development and just enough restriction required for family harmony and for the safety of the child.”
—Selma H. Fraiberg (20th century)
“But you must pay for conformity. All goes well as long as you run with conformists. But you, who are honest men in other particulars, know, that there is alive somewhere a man whose honesty reaches to this point also, that he shall not kneel to false gods, and, on the day when you meet him, you sink into the class of counterfeits.”
—Ralph Waldo Emerson (1803–1882)