CELL DIVISION
THE CELL CYCLE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Mature nerve cells are in a resting state (G0); they no longer divide during mitosis
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Nerve damage disrupts the cell cycle at the G1 phase
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Nerve damage disrupts the cell cycle at the S phase
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Nerve damage prevents centrioles from being synthesized
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Detailed explanation-1: -Spinal cord injuries are difficult to treat because damaged nerve cells do not regenerate. Which of the following most accurately explains why damaged nerve cells no longer regenerate? Mature nerve cells are in a permanent mitotic state; they no longer divide.
Detailed explanation-2: -Damage to the spinal cord rarely heals because the injured nerve cells fail to regenerate. The regrowth of their long nerve fibers is hindered by scar tissue and molecular processes inside the nerves. Scientists in now report that help might be on the way from an unexpected quarter.
Detailed explanation-3: -Growth or standstill It has now become clear that there are a whole number of substances in the central nervous system which prevent the nerve cells regrowing. These substances do not occur in the peripheral nervous system, so there is nothing to stop regeneration there.
Detailed explanation-4: -People who survive severe spinal cord injuries often experience life-long disability. Adult nerve cells in the spinal cord don’t regrow after damage. Why they don’t, and how they might be encouraged to do so, have been areas of extensive research. Axons require a great deal of energy to regrow.
Detailed explanation-5: -There is absence of centrioles in the nerve cells and because of this they are unable to perform mitosis and meiosis and hence these cells do not divide. But nerve cells get longer without dividing and they do not divide during their lifetime.