what happens in g1

The G1 phase is the first phase of the cell cycle that takes place in eukaryotic cell division. During this phase, cells grow in size and synthesize mRNA and protein that are required for DNA synthesis. The duration of the G1 phase is variable and depends on the nutrients that are available to a cell. At the end of the G1 phase, cells have a "restriction point," which is a safeguard that ensures that protein synthesis occurred properly and the cells DNA is intact and ready for the future stages. If the cell is signaled to remain undivided, instead of moving onto the S phase, it will leave the G1 phase and move into a state of dormancy called the G0 phase.