Question

Which of the following cells permanently enter into G${}_0$ Phase ?

• A. Nerve cells
• B. Parenchyma cells
• C. Meristematic cells
• D. All cells of animals

Answer 1

The correct option is A Nerve cells

The cells that do not divide further, exit the cell cycle in the $G_1$ phase and enter into a quiescent (dormant) stage called G${}_0$ phase. Cells in the $G_0$ stage remain metabolically active but no longer divide.

Some cells enter the $G_0$ phase temporarily and some enter permanently.
Nerve cells permanently enter the $G_0$ phase. They further cannot divide as they lack centrioles.
Meristematic cells are actively dividing cells and, hence, do not enter the $G_0$ phase.
Parenchyma cells are permanent cells but they can regain the capacity to divide and help in secondary growth of the plant body. For example, cambium is a meristematic tissue which is made up of meristematic cells and parenchyma cells which have gained the meristematic capability again.

Cells of adult animals do not exhibit division, but during injury, cells start to divide forming new cells to replace the lost cells. The gonads of adult animals divide by meiosis to form gametes.