Why are the leading and lagging strands of DNA molecules synthesized differently?
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An illustration to show replication of the leading and lagging strands of DNA. Leading Strand:
Lagging strand:
This page was last updated on 2021-07-21
Highlights• Simultaneous imaging of leading- and lagging-strand synthesis by single replisomes •Most loop formation events on the lagging strand occur during primer synthesis •Polymerases are released from the replisome to complete Okazaki-fragment synthesis •Multiple pathways and exchange events underlie replisome coordination SummaryThe molecular machinery responsible for DNA replication, the replisome, must efficiently coordinate DNA unwinding with priming and synthesis to complete duplication of both strands. Due to the anti-parallel nature of DNA, the leading strand is copied continuously, while the lagging strand is produced by repeated cycles of priming, DNA looping, and Okazaki-fragment synthesis. Here, we report a multidimensional single-molecule approach to visualize this coordination in the bacteriophage T7 replisome by simultaneously monitoring the kinetics of loop growth and leading-strand synthesis. We show that loops in the lagging strand predominantly occur during priming and only infrequently support subsequent Okazaki-fragment synthesis. Fluorescence imaging reveals polymerases remaining bound to the lagging strand behind the replication fork, consistent with Okazaki-fragment synthesis behind and independent of the replication complex. Individual replisomes display both looping and pausing during priming, reconciling divergent models for the regulation of primer synthesis and revealing an underlying plasticity in replisome operation. KeywordsDNA replication bacteriophage T7 flow stretching single molecule Cited by (0)© 2016 Elsevier Inc. Why are the leading and lagging strands of DNA synthesized differently during DNA replication quizlet?It catalyzes the addition of nucleotides to the 3' end of a growing DNA strand. Why are Leading and Lagging strands created during DNA Replication? They are created because new DNA can be synthesized only in a 5'->3' direction. The template of the DNA is therefore always 3'-5'.
How are leading and lagging strands synthesized differently quizlet?the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.
What is the basis for the difference in the synthesis of the leading and lagging strand of DNA molecules?DNA polymerase only synthesizes DNA in the 5' to 3' direction only. The difference between the leading and lagging strands is that the leading strand is formed towards replication fork, while the lagging strand is formed away from replication fork.
Why synthesis on the lagging strand is slower than the synthesis on the leading strand?This delay occurs because DNA polymerization on the lagging strand is forced to occur in the direction going away from the replication fork.
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