Biology / Unit 6 Bio 1227 short lesson, about 20 seconds
DNA Ligase
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The idea
DNA ligase seals the remaining gap between adjacent Okazaki fragments, once their RNA primers are removed and replaced with DNA, forming one continuous strand.
In practice
Ligase catalyzes a phosphodiester bond between one fragment's 3' end and the next fragment's 5' end.
Where people slip
Ligase joins DNA fragments together — removing the RNA primers first is a separate step, performed by a different enzyme's exonuclease activity.
Your place on the trail
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