Cells which no longer divide (such as certain specialized cells found in the human brain) remain in which phase of the cell cycle?
A.Prophase
B. S phase
C. G0 Phase
D. Gl Phase
Answers
Dear respected student,
Starting phase of the cell cycle especially in human brain cells are not further showing any cellular differentiation or any proper division that just means it's in it's first phase, that is, G0 phase.
If a cell has the ability to divide thoroughly the cell continues the cell cycle and goes through two stages and it has two options, either to remain in the G0 phase and never show any division or to go further and continue to complete their cell division (by entering the synthetic phase or the S-phase or completely stopping the whole cell cycle and restricting itself to the G0 phase).
In the brain and the cells showing the ability for totipotency like stem cells, they're in a post mitotic phase that is, they've completed the cell cycle or division in the mitotic cellular differentiation process.
Cells which are post-mitotic can't actually show further differentiation and neither regenerate by the rest of the life, instead they're dormant like, in a G0 phase, and will never show the ability to transfer themselves into a "new cell cycle", they'll always remain in G0 phase.
To further contradict, that's the prime reason when a person, when he receives a physical brain injury which internally affects the structures inside the brain, it'll be impossible to recover from that stage.
If they're harmed, the neuronal cells never recover, it's completely permanent as neuronal cells (as said before) are in a literal "dormant state", will never show any differentiation, contribution to the cell cycle, replication of cells in cell division, etc.
They also lack the centrioles which're needed for further cell division of anaphase and metaphase, because of which a permanent quinessence stage is 100% ensured, no division, no replication, remains in the G0 phase till death of the organism.
Hence, the factually and the most obvious universal option will definitely become, Option C) G0 phase, such complex cellular structures lacking the centrioles needed for differentiation of cellular matrix and cytoplasmic matrix and nucleus, plus remaining in the G0 phase for the lifetime, is often a significance of the human brain cells (nerve cells, glial cells, except the ability of condensation in post mitotic phase).
Hope this helps you and clears your doubts for nerve cells in Brain, never having the capability to divide !!!!!