In this phase, the cell also produces a small amount of proteins and organelles. But the majority of the resources of the cell basically focus on DNA replication. Now, in human cells, all 46 individual chromosomes are actually replicated. And the original chromosome and the replicated chromosome are joined together in a region known as the centromere, which involves different types of proteins that assist in the joining process. So let's take a look at the following diagram. So, at the beginning of S phase, we have individual original chromosomes.