DNA Replication - Summary
Biology: IB Diploma Higher Level, topic 1.2.5
DNA Replication Summary
There's a lot to take in, huh? Let's re-summarize DNA replication below - you got this :-)
Summary - 1
- DNA unwinds at the origin of replication.
- Helicase opens up the DNA-forming replication forks; these are extended bidirectionally.
- Single-strand binding proteins coat the DNA around the replication fork to prevent rewinding of the DNA.
- Topoisomerase binds at the region ahead of the replication fork to prevent supercoiling.
Summary - 2
- Primase synthesizes RNA primers complementary to the DNA strand.
- DNA polymerase starts adding nucleotides to the 3'-OH end of the primer.
- Elongation of both the lagging and the leading strand continues.
- RNA primers are removed by exonuclease activity.
- Gaps are filled by DNA pol by adding dNTPs.
- The gap between the two DNA fragments is sealed by DNA ligase, which helps in the formation of phosphodiester bonds.
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Test yourself on DNA Replication - Summary
Where does DNA unwind?
Which enzyme synthesizes RNA primers needed to start replication?
What does the sliding clamp do?