where does dna replication begin on a chromosome
Origin of replication DNA replication may proceed from this point bidirectionally or unidirectionally.[3]
DNA replication For a cell to divide, it must first replicate its DNA.[11] This process is initiated at particular points in the DNA, known as "origins", which are targeted by initiator proteins.[4] In E. coli this protein is DnaA; in yeast, this is the origin recognition complex.[12] Sequences used by initiator proteins tend to be "AT-rich" (rich in adenine and thymine bases), because A-T base pairs have two hydrogen bonds (rather than the three formed in a C-G pair) and thus are easier to strand-separate.[13] Once the origin has been located, these initiators recruit other proteins and form the pre-replication complex, which unwinds the double-stranded DNA.
DNA replication For a cell to divide, it must first replicate its DNA.[10] This process is initiated at particular points in the DNA, known as "origins", which are targeted by initiator proteins.[3] In E. coli this protein is DnaA; in yeast, this is the origin recognition complex.[11] Sequences used by initiator proteins tend to be "AT-rich" (rich in adenine and thymine bases), because A-T base pairs have two hydrogen bonds (rather than the three formed in a C-G pair) and thus are easier to strand-separate.[12] Once the origin has been located, these initiators recruit other proteins and form the pre-replication complex, which unwinds the double-stranded DNA.
DNA replication Within eukaryotes, DNA replication is controlled within the context of the cell cycle. As the cell grows and divides, it progresses through stages in the cell cycle; DNA replication takes place during the S phase (synthesis phase). The progress of the eukaryotic cell through the cycle is controlled by cell cycle checkpoints. Progression through checkpoints is controlled through complex interactions between various proteins, including cyclins and cyclin-dependent kinases.[27] Unlike bacteria, eukaryotic DNA replicates in the confines of the nucleus.[28]