G2 phase
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- The correct title of this article is G2 phase. It features superscript or subscript characters that are substituted or omitted because of technical limitations.
G2 phase is a the 3rd and final subphase in interphase of the cell cycle. It follows successful completion of DNA synthesis and chromosomal replication in S phase, and occurs during a period of time - often four to five hours. This far into interphase the nucleus is well defined and bounced by a nuclear envelope. It contains at least one nucleolus. Although the chromosomes have been replicated they can not yet be distinguished individually because they are still in the form of loosely packed chromatin fibers. The phase prepares the cell for mitosis, or M phase, initiated by prophase.
At the end of this gap is another control checkpoint, the G2 Checkpoint, to determine if the cell can now proceed to enter M phase and divide. The G2 checkpoint prevents cells from entering mitosis when DNA was damaged since the last division, providing an opportunity for DNA repair and stopping the proliferation of damaged cells. Because the G2 checkpoint helps to maintain genomic stability, it is an important focus in understanding the molecular causes of cancer.
| Preceded by: S phase | Steps in the cell cycle | Succeeded by: prophase |
