Normal
cells do not grow and divide haphazardly. They are tightly regulated in
a cycle, complete with checkpoints, to make sure everything is growing
properly.
Gap 0 (G0) is a post-mitotic resting place for the
cell, in which no growth or replication is occurring. Nonproliferative
cells, such as neurons, can remain in G0 indefinitely, while other
cells, such as liver cells, can remain for long pe
riods
of time, but can enter back into the cell cycle when needed. Following
mitosis, a cell can either rest in G0, or move directly into Gap 1.
G1 marks the beginning of interphase. The cell begins to create lots of
proteins and enzymes for later use in the cycle. At the end of G1, the
cell stops to assess the progress. If everything is not in order, the
cycle does not move forward, and takes more time to grow.
Synthesis (S) phase follows G1. DNA is copied, and sister chromatid (two
identical copies of the same chromosome) join to form a single unit.
There is extensive proofreading that occurs during S phase. Before the
cell clears the checkpoint, it must be ensured that the DNA has been
copied correctly. The checkpoint will give it time to edit any mistakes,
or, if the damage is too extensive, it will go into apoptosis,
destroying the cell.
Gap 2 is the last step in the cell cycle
of interphase, before division occurs. Microtubules needed during
mitosis are created in G2. If everything has been developed correctly
during the cell cycle, it is ready to enter mitosis and make an
identical copy of itself.
For more information: http://
Normal
cells do not grow and divide haphazardly. They are tightly regulated in
a cycle, complete with checkpoints, to make sure everything is growing
properly.
Gap 0 (G0) is a post-mitotic resting place for the cell, in which no growth or replication is occurring. Nonproliferative cells, such as neurons, can remain in G0 indefinitely, while other cells, such as liver cells, can remain for long pe
Gap 0 (G0) is a post-mitotic resting place for the cell, in which no growth or replication is occurring. Nonproliferative cells, such as neurons, can remain in G0 indefinitely, while other cells, such as liver cells, can remain for long pe
riods
of time, but can enter back into the cell cycle when needed. Following
mitosis, a cell can either rest in G0, or move directly into Gap 1.
G1 marks the beginning of interphase. The cell begins to create lots of proteins and enzymes for later use in the cycle. At the end of G1, the cell stops to assess the progress. If everything is not in order, the cycle does not move forward, and takes more time to grow.
Synthesis (S) phase follows G1. DNA is copied, and sister chromatid (two identical copies of the same chromosome) join to form a single unit. There is extensive proofreading that occurs during S phase. Before the cell clears the checkpoint, it must be ensured that the DNA has been copied correctly. The checkpoint will give it time to edit any mistakes, or, if the damage is too extensive, it will go into apoptosis, destroying the cell.
Gap 2 is the last step in the cell cycle of interphase, before division occurs. Microtubules needed during mitosis are created in G2. If everything has been developed correctly during the cell cycle, it is ready to enter mitosis and make an identical copy of itself.
For more information: http://
G1 marks the beginning of interphase. The cell begins to create lots of proteins and enzymes for later use in the cycle. At the end of G1, the cell stops to assess the progress. If everything is not in order, the cycle does not move forward, and takes more time to grow.
Synthesis (S) phase follows G1. DNA is copied, and sister chromatid (two identical copies of the same chromosome) join to form a single unit. There is extensive proofreading that occurs during S phase. Before the cell clears the checkpoint, it must be ensured that the DNA has been copied correctly. The checkpoint will give it time to edit any mistakes, or, if the damage is too extensive, it will go into apoptosis, destroying the cell.
Gap 2 is the last step in the cell cycle of interphase, before division occurs. Microtubules needed during mitosis are created in G2. If everything has been developed correctly during the cell cycle, it is ready to enter mitosis and make an identical copy of itself.
For more information: http://
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