<P> Okazaki fragments are short, newly synthesized DNA fragments that are formed on the lagging template strand during DNA replication . They are complementary to the lagging template strand, together forming short double - stranded DNA sections . Okazaki fragments are between 1000 and 2000 nucleotides long in prokaryotes (e.g. Escherichia coli) and are roughly 100 to 200 nucleotides long in eukaryotes . They are separated by ~ 120 - nucleotide RNA primers and are unligated until RNA primers are removed, followed by enzyme ligase connecting (ligating) an Okazaki fragment onto the (now continuous) newly synthesized complementary strand . </P> <P> On the leading strand DNA replication proceeds continuously along the DNA molecule as the parent double - stranded DNA is unwound, but on the lagging strand the new DNA is made in installments, which are later joined together by a DNA ligase enzyme . This is because the enzymes that synthesise the new DNA can only work in one direction along the parent DNA molecule and the two strands are anti-parallel . On the leading strand this route is continuous, but on the lagging strand it is discontinuous . </P> <P> DNA is synthesised from 5' to 3', so when copying the 3' to 5' strand, replication is continuous . Phosphodiester links form between the 3' to 5' and nucleotides can be added with the aid of the enzyme DNA polymerase for the continuous leading strand . However, in order to synthesise the lagging strand (the 5' to 3' strand) synthesis must occur in small sections (100 - 200 nucleotides at a time in eukaryotes). These new stretches of DNA are called Okazaki fragments and each one requires its own RNA primer . </P>

Okazaki fragments are mended together by which type of enzymes