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DNA Replication in Prokaryotes

6 April, 2016 - 17:26

Recall that the prokaryotic chromosome is a circular molecule with a less extensive coiling structure than eukaryotic chromosomes. The eukaryotic chromosome is linear and highly coiled around proteins. While there are many similarities in the DNA replication process, these structural differences necessitate some differences in the DNA replication process in these two life forms.

DNA replication has been extremely well-studied in prokaryotes, primarily because of the small size of the genome and large number of variants available. Escherichiacoli has 4.6 million base pairs in a single circular chromosome, and all of it gets replicated in approximately 42 minutes, starting from a single origin of replication and proceeding around the chromosome in both directions. This means that approximately 1000 nucleotides are added per second. The process is much more rapid than in eukaryotes. Table 9.1 summarizes the differences between prokaryotic and eukaryotic replications.

Table 9.1 Differences between Prokaryotic and Eukaryotic Replications

Property

Prokaryotes

Eukaryotes

Origin of replication

Single

Multiple

Rate of replication

1000 nucleotides/s

50 to 100 nucleotides/s

Chromosome structure

circular

linear

Telomerase

Not present

Present

 

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Click through a tutorial (http://openstaxcollege.org/l/DNA_replicatio2) on DNA replication.