Growth arrest or G0 is viewed as either an extended G1 phase, where the cell stops growing (in M phase) due to mutation/damage, due to contact inhibition (crowding), or lack of food.
Not all cells adhere to the normal cell cycle pattern in which a newly-formed daughter cell immediately enters the interphase, closely followed by the mitotic phase. Cells in G0 phase are not actively preparing to divide. The cell is in a quiescent (inactive) stage that occurs when cells exit the cell cycle. Some cells enter G0 temporarily until an external signal triggers the onset of G1. Other cells that never or rarely divide, such as mature cardiac muscle and nerve cells, remain in G0 permanently.
• Cells that are not actively preparing to divide enter an alternate phase called G0.
• G0 is a temporary condition until triggered to enter G1, while some remain in G0 permanently.
quiescent: in a state or period of inactivity or dormancy