Which phase of the cell cycle involves preparation for DNA replication?

The G1 phase, or Gap 1 phase, is the part of the cell cycle where the cell grows and prepares for DNA replication. During this phase, the cell increases in size, produces RNA, synthesizes proteins, and organizes cellular components necessary for DNA synthesis. This preparation includes ensuring that all the necessary enzymes and substrates for DNA replication are available, as well as checking for any potential damage to the DNA. As the cell processes nutrients and gathers the required materials, it also monitors its environment and conditions to ensure it is ready to enter the next phase, the S phase, where DNA replication actually occurs.

In contrast, the S phase is specifically when DNA replication takes place, G2 is focused on further growth and preparation for cell division, and M phase is when the cell actually divides. Therefore, the G1 phase is essential as it lays the groundwork for a successful and accurate DNA replication process.