The G₀ phase is a period in the cell cycle

Cell cycle

The cell cycle, or cell-division cycle, is the series of events that takes place in a cell leading to its division and duplication . In cells without a nucleus , the cell cycle occurs via a process termed binary fission...

 in which cells exist in a quiescent

Quiescence

Quiescence may refer to:*Quiescence search, in Game searching in artificial intelligence, a quiescent state is one in which a game is considered stable and unlikely to change drastically the next few plays...

 state. G₀ phase is viewed as either an extended G₁ phase

G1 phase

The G1 phase is a period in the cell cycle during interphase, before the S phase. For many cells, this phase is the major period of cell growth during its lifespan. During this stage new organelles are being synthesized, so the cell requires both structural proteins and enzymes, resulting in great...

, where the cell is neither dividing nor preparing to divide, or a distinct quiescent stage that occurs outside of the cell cycle. G₀ is sometimes referred to as a "post-mitotic" state, since cells in G₀ are in a non-dividing

Cell division

Cell division is the process by which a parent cell divides into two or more daughter cells . Cell division is usually a small segment of a larger cell cycle. This type of cell division in eukaryotes is known as mitosis, and leaves the daughter cell capable of dividing again. The corresponding sort...

 phase outside of the cell cycle

Cell cycle

The cell cycle, or cell-division cycle, is the series of events that takes place in a cell leading to its division and duplication . In cells without a nucleus , the cell cycle occurs via a process termed binary fission...

.