Question

What is G0(quiescent phase) of cell cycle?

Answer 1

Hint: The series of events which a cell undergoes for its division and growth is called cell cycle. It includes the preparatory phase and the division phase. The interphase is the preparatory phase followed by the division phase which includes mitosis and cytokinesis and the G0 phase.

Complete Answer:
- Interphase: It comprises G1 and G2 phases. In this the cell does not show any kind of physical changes rather the DNA, mRNA and protein duplication and synthesis takes place. It is also known as the preparatory phase. The cell further enters the mitosis.
- Mitosis: In this phase the cell divides into two daughter cells. It consists of prophase, metaphase, anaphase and telophase followed by the division of cytoplasm.
- G0 phase is the phase of the cell outside the replicative stage. It is thought to be the resting phase. The cell enters this state when there is limited nutrient, or certain environmental limitation. The quiescence stage of G0 is a reversible stage where the cells are in this stage just after the G1 phase but before entering the cell cycle.
- In this stage, the cell has low mRNA, or some proliferation markers may be missing. The cells remain in this stage so as to prevent faulty division.
- Application of G0 phase in stem cells- the cells in this stage are active and are able to repair injury. Thus, this state is considered as an adaptive response of the cell to deal with the injury or stress before entering the dividing phase.

Note: The adult neuron cells permanently reside in the G0 phase. These cells are fully differentiated and are metabolically active but do not divide. This is due to the internal genetics of the neuronal cells. The mature hepatocytes also stay in the quiescent stage.