DNA Replication in Eukaryotes:

DNA replication in eukaryotes is much more difficult than in prokaryotes while there are several same aspects. The Eukaryotic cells can only initiate DNA replication at a specific point in the cell cycle, the starting of S phase.  The DNA replication in eukaryotes occurs only in the S phase of the cell cycle. Moreover, pre-initiation occurs in the G1 phase. Therefore, pre-initiation and activation needs two very several intra-cellular contexts to follow every other in the right order making it very unlikely which replication will take place more than once per cell cycle.

With the Due to the sheer size of chromosomes in eukaryotes and eukaryotic chromosomes hold multiple origins of replication. Some origins are well characterized, such as the ARS (autonomously replicating sequences) of yeast although other eukaryotic origins, particularly those in metazoan which can be found in spans of thousands of basepairs. However, the initiation and assembly of replicaton is same in both the metazoa and protozoa.