ABSTRACT
In eukaryotes, the cell cycle consists of G1, S, G2 and M phases. Most differences in the cycle times of different cells are due to differences in the length of the G1 phase. DNA replication occurs only in the S phase. It occurs at many chromosomal origins, is bi-directional and semi-conservative. The life of a eukaryotic cell can be defined as a cell cycle. In eukaryotes, replication of chromosomal DNA occurs only in the S phase of the cell cycle. Eukaryotic cells contain five different DNA polymerases; α, β, γ, δ and ε. The DNA polymerases involved in replication of chromosomal DNA are a and d. The basic scheme of replication of double-stranded chromosomal DNA in eukaryotes follows that for bacterial DNA replication; a leading strand and a lagging strand are synthesized, the latter involving discontinuous synthesis via Okazaki fragments.
