Well, DNA is replicated before mitosis, division of body cells, and before meiosis, the division of sex cells. Before dividing, however, DNA is in the form of chromatin (a threadlike substance that is wrapped around proteins in the nucleus). It divides automatically before mitosis or meiosis so that each daughter cell has the same amount of chromosomes. I do not believe any "materials" are needed for replication. In other words, it just happens.