Interphase has three parts, G1, S, and G2. G1, or gap 1, is where the cells grow and make both organelles and proteins. In S, or synthesis, the DNA is replicated so the chromosomes are made of two sister chromatids. In G2, or gap 2, the cell makes microtubules, centromeres, and centrioles. There is also a phase called G0, which isn’t part of growing or dividing. This is where cells rest, and some cells stay here for their whole life.