cellular biology wiz needed 6) Fusion of an S-phase cell with a G1 cell caused t
ID: 214609 • Letter: C
Question
cellular biology wiz needed
6) Fusion of an S-phase cell with a G1 cell caused the G1 nucleus to enter S-phase and replicate its DNA. However, fusion of an S-phase cell with a G2 cell (post-DNA replication) did not cause the G2 cell to replicate its DNA again. This suggested that the G1 cell lacks something that the S-phase cell provides for S-phage entry and that the G2 and S-phase cells lack something that the G1 cell provides to elicit DNA replication. What does the S- phase cell contain that the G1 phase cell does not to enable S-phase entry? What does the G2-phase cell lack that the S-phase cell cannot provide for replication to occur again?Explain. (2 points) Bonus: How could you mutate the codon for S795 so that it can never be phosphorylated? Explain. (2 points)Explanation / Answer
The cell cycle is regulated by cyclins and cyclin-dependent kinases (CDKs). The cyclins are the regulatory proteins while the CDKs are catalytic in function. To regulate a cell cycle the heteromer Cyclin-CDK are required. The Cyclin-dependent kinases phosphorylate only when activated by the Cyclins.
The G1 cyclin-CDK complex prepares the cell for the Synthetic (S) phase. This happens due to the expression of transcription factors and the expression of enzymes that are involved in the DNA replication. The G1 cyclin-CDK complex also degrade the inhibitors of S phase.
Active S cyclin-CDK complex function to phosphorylate the proteins of pre-replication complexes that were assembled during the G1 phase.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.