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Multiple Choice
Can cells exit the $G_0$ phase and re-enter the cell cycle under certain conditions?
A
Only prokaryotic cells can leave $G_0$; eukaryotic cells cannot.
B
Cells in $G_0$ are always actively dividing.
C
No, once cells enter $G_0$, they are permanently unable to divide.
D
Yes, some cells can leave $G_0$ and re-enter the cell cycle in response to specific signals.
Verified step by step guidance
1
Understand the concept of the $G_0$ phase: The $G_0$ phase is a resting or quiescent state in the cell cycle where cells are not actively dividing. Cells in this phase have exited the normal cycle of growth and division (the $G_1$, $S$, $G_2$, and M phases).
Recognize that the ability to leave $G_0$ depends on the type of cell: Some eukaryotic cells, such as liver cells and certain immune cells, can exit $G_0$ and re-enter the cell cycle when stimulated by specific signals like growth factors or injury repair signals.
Clarify the incorrect statements: Prokaryotic cells do not have a $G_0$ phase because their cell cycle is simpler and lacks the distinct phases seen in eukaryotic cells. Additionally, cells in $G_0$ are not actively dividing; they are in a state of dormancy or specialized function. Finally, not all cells are permanently unable to divide after entering $G_0$; some can re-enter the cycle under certain conditions.
Explain the correct answer: Yes, some eukaryotic cells can leave $G_0$ and re-enter the cell cycle in response to specific signals. This process is essential for tissue repair, immune responses, and other biological functions.
Summarize the key takeaway: The $G_0$ phase is not necessarily a permanent state for all cells. Certain eukaryotic cells retain the ability to re-enter the cell cycle when prompted by external signals, highlighting the dynamic nature of cellular processes.