Short DNA segments synthesised discontinuously on the lagging strand and joined by DNA ligase.
Fragments are 100 to 200 nucleotides in eukaryotes and 1000 to 2000 in bacteria. After primers are removed and gaps filled by DNA polymerase, DNA ligase seals the nicks. Discovered by Reiji Okazaki in the 1960s.
Defects in ligase cause genome instability.
Short DNA segments synthesised discontinuously on the lagging strand and joined by DNA ligase.
Okazaki Fragments is one of the 52 topics in Molecular Biology. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Leading and Lagging Strands, DNA Polymerase, Primase and RNA Primer.
Processing fragments takes a flap endonuclease (FEN1) in eukaryotes.
Work through the Beginner topics in Molecular Biology first, such as Central Dogma, DNA Replication, Base Pairing, then return to Okazaki Fragments. Intermediate topics assume the Beginner vocabulary.
The closest topics to Okazaki Fragments are Leading and Lagging Strands, DNA Polymerase, Primase and RNA Primer, RNA Polymerase. Comparing them side by side is a good way to see how the ideas connect.
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Okazaki Fragments. To practise the whole of Molecular Biology, use the Molecular Biology quiz.
Okazaki Fragments: Short DNA segments synthesised discontinuously on the lagging strand and joined by DNA ligase. Leading and Lagging Strands: The leading strand is made continuously, while the lagging strand is made in short Okazaki fragments. Read both side by side and note what each one explains.
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Leading and Lagging Strands and explain the difference aloud. Finally, take the Molecular Biology quiz and come back to this page for any question you miss.
The leading strand is made continuously, while the lagging strand is made in short Okazaki fragments.
🧫 Molecular BiologyThe enzyme that adds nucleotides to a growing DNA strand in the 5 prime to 3 prime direction.
🧫 Molecular BiologyPrimase lays down a short RNA primer that gives DNA polymerase a starting 3 prime end.
🧫 Molecular BiologyThe enzyme that builds an RNA strand complementary to the template DNA during transcription.
🧫 Molecular Biology