Which phase of the cell cycle occurs first

Your answer is interphase. The part of the cell cycle when the cell is growing, becoming a full cell.

Concept 2: Mitosis and the Cell Division Cycle. Cells that are growing and dividing go through a repeating series of events called the cell division cycle (or cellcycle). During the firstphase (G1), the cell grows and prepares for DNA replication, which occurs in the subsequent S phase.