Topic A: Cell Cycle
1) What regulates the expression of these proteins?
The expression of these proteins, especially cyclins and kinases are regulated by cell cycle checkpoints. Ideally, these checkpoints are used for the purpose of preventing cell cycle progression at certain points, permitting verification of processes that takes in each phase as well as the repairing of damaged DNA (Lieberman 3).
2) Since several hundreds of proteins are involved and exact ″formula″ of how much expression of each should be present is necessary at different stages, how does the cell recognize the protein expression levels necessary to either continue through the cell cycle or terminate/apoptize?
In order to recognize the protein expression levels necessary to either continue through the cell cycle or terminate/ apoptize it, it ensures that the checkpoint requirements have been met before proceeding to the next phase. These checkpoints include the G1/S, the G2/M, and the mitotic (metaphase) checkpoints. The G1/S checkpoint is used to confirm whether it contains sufficient raw materials for complete DNA replication. The G2/M checkpoint takes the responsibility of ensuring that it contains sufficient phospholipids and cytoplasm materials for the two daughter cells as well as confirming whether it is the right time for replication. The mitotic (metaphase) checkpoint is used to confirm whether the spindle has been formed. Likewise, before anaphase begins, this checkpoint is used to validate whether the chromosomes have been line up at the spindle equator (Thiriet 114).
Topic B: Apoptosis
1) How does the body know where to resorb these structures and how far back to apoptize the cells that make them up?
During apoptosis, the small chunks that are produced are tidily enclosed or wrap up in a membrane. In order for the body to know where to resorb them, it depends on signals, either from outside or inside the cell, that aid in attracting phagocytic or debris-eating immune cells, for instance, macrophages. The body also depends on instructions and instruments that aid in dictating how far back to apoptize the cells that make those structures (Preedy et al 1302).
2) How does the body know when to turn this apoptotic signaling on during development so these events don′t happen too soon or too late?
The body depends on the inactive proenzyme called procaspase, which later becomes peroteolytic caspases after activation. To ensure that these events do not happen too soon or too late, they ensure that the cellular components are destroyed in an organized manner. This, in return, assists in ensuring that surrounding tissues has not been affected after apoptotic signaling (Garland Science 1119).
Work cited
Garland Science.Molecular Biology of the Cell, 5th Ed, 2008: Cell: Volume 1 of Molecular Biology of the Cell. Bukupedia , 2008. Print
Lieberman, Howard B. Cell Cycle Checkpoint Control Protocols. Totowa, N.J: Humana Press, 2004. Print.
Preedy, Victor R, and Ronald R. Watson. Olives and Olive Oil in Health and Disease Prevention. Amsterdam: Elsevier, 2010. Internet resource.
Thiriet, Marc. Control of Cell Fate in the Circulatory and Ventilatory Systems. New York: Springer, 2011. Internet resource.
