Question

Radiation Maddi La his as ere the dodge 23. According to Model 3, ultraviolet light is affecting a cell in which phase of the cell cyde! 24. Ultraviolet light may cause DNA damage, which is known as a mutation. How might such dam. age affect events taking place during the synthesis phase? Hint: Use information from Model 2. Read This! The cell cycle has a regular system of checks and balances that prevents damaged or mutated cells from proceeding to the next phase. One way an organism deals with the problems is to kill the damaged cell before it passes on the problem to its daughter cells. This is a normal process called apoptosis. (Some normal cells also go through this process.) 25. How might the DNA damage go on to affect the rest of the cell cycle if apoptosis did not occur? 26. Why might it be beneficial to an organism for damaged cells to enter G, instead of dividing once they exist? 27. What could happen, after several cell cycles, to an organism whose damaged cells did not go through apoptosis? In other words, what if a damaged cell that is supposed to die does not? The Cell Cycle

Answer 1

Dear Student

23. According to model 3 , ultra violet ray is affecting the cell in G₁ phase.

24.The G₁ checkpoint is the main decision point for a cell that is, the primary point at which it must choose whether or not to divide. Once the cell passes the G₁ checkpoint and enters S phase, it becomes irreversibly committed to division. That is, barring unexpected problems, such as DNA damage or replication errors, a cell that passes the G₁ checkpoint will continue the rest of the way through the cell cycle and produce two daughter cells.

If DNA damage has taken place in G₁ phase and mutation has occurred then this will result in replication of the damaged DNA in the new cell. Eventually all daughter cells of the mutated cell will be mutated.

25. If apoptosis did not occur then the mutated cell will replicate and the mutated DNA will spread into all the other cells.

26. It is beneficial a damaged cell to enter G0 instead of dividing because the damaged cell will not create more damaged cells.   

27. If apoptosis or cell death did not occur then it can cause various health issues in organisms .

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