The interphase is the period of the cellular cycle which is characterized by an increase in cellular volume, the cell transcribes its genes and the chromosomes are duplicated. It can be subdivided in several phases:

• the phase G1 (of English Growth 1, or Gap 1) during which the cell grows and carries out the functions for which it is programmed genetically: proteinic synthesis, etc In particular, during this phase, the cells girls, resulting from the preceding mitosis and thus smaller, take their final size.

• the phase S (Synthesis = Synthesis of new molecule of DNA) during which the chromosomal material is doubled by Réplication each Chromosome S.
• the phase G2 (Growth 2 or Gap 2) where the cell prepares to be divided into two cells girls. At the conclusion of this phase, each chromosome is perfectly identical (morphology and genetics) to its counterpart.

for more detail to see:

cellular Cycle