Many times a cell will leave the cell cycle ,temporarily or permantently. It exists the cycle at G1 and enters a stage designated G0.(resting phase) It is also called as quiscent stage where the cell is neither dividing nor preparing to divide.
Often G0 cells are terminally differentiated they will never re-enter the cell cycle but instead will carry out their function in the organism untill they die.
Hepatocytes in the normal liver are quiesent (G0 stage ).
G0 represents not simply the absence of signals for mitosis but an active repression of the genes needed for mitosis. Cancer cells cannot enter Go stage as they are designed to repeat the cell cycle indefinitely .
Some types of cells, such as nerve and heart muscle cells, neurons become quiescent when they reach maturity but continue to perform their main functions for the rest of the organism's life. Multinucleated muscle cells that do not undergo cytokinesis are also often considered to be in the G0 stage.
During the G0 phase, the cell cycle machinery is dismantled and cyclins and cyclin-dependent kinases disappear.
Image source-https://14milema.files.wordpress.com/2010/10/cellcycle2.png
The importance of G0 phase - During cell division when the cell get a signal that there are enough of cells or there is a mutation in the cell that need to be fixed before they differentiate fully or the cell during its division gets damage then it is signalled to rest, and it is this phase that cell leave the cycle and quit dividing. It could be temporary resting period (so when cell again required, or damaged got fixed) then the cells will again join the cycle and continue to divide again or it can also be permanent for example neurons, which are resting in G0 phase and never divides again.
1.
Terminally differentiated cells are most often found in which phase of the cell cycle?
A. G0
B. G1
C. G2
D. M
Ans. A
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Often G0 cells are terminally differentiated they will never re-enter the cell cycle but instead will carry out their function in the organism untill they die.
Hepatocytes in the normal liver are quiesent (G0 stage ).
G0 represents not simply the absence of signals for mitosis but an active repression of the genes needed for mitosis. Cancer cells cannot enter Go stage as they are designed to repeat the cell cycle indefinitely .
Some types of cells, such as nerve and heart muscle cells, neurons become quiescent when they reach maturity but continue to perform their main functions for the rest of the organism's life. Multinucleated muscle cells that do not undergo cytokinesis are also often considered to be in the G0 stage.
During the G0 phase, the cell cycle machinery is dismantled and cyclins and cyclin-dependent kinases disappear.
Image source-https://14milema.files.wordpress.com/2010/10/cellcycle2.png
The importance of G0 phase - During cell division when the cell get a signal that there are enough of cells or there is a mutation in the cell that need to be fixed before they differentiate fully or the cell during its division gets damage then it is signalled to rest, and it is this phase that cell leave the cycle and quit dividing. It could be temporary resting period (so when cell again required, or damaged got fixed) then the cells will again join the cycle and continue to divide again or it can also be permanent for example neurons, which are resting in G0 phase and never divides again.
1.
Terminally differentiated cells are most often found in which phase of the cell cycle?
A. G0
B. G1
C. G2
D. M
Ans. A
Thank you for visiting my blog.Please feel free to share your comment on this article ,Please subscribe and share the articles to get more such articles.
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