One of the issues with DNA replication is that both strands of the anti-parallel
ID: 151715 • Letter: O
Question
One of the issues with DNA replication is that both strands of the anti-parallel helix must be replicated simultaneously. How does the cell replicate both strands in the same direction (ie: to the right) even though the strands are anti-parallel?
Replication is bi-directional
Replication builds one strand 5' to 3' and the other from 3' to 5'
One strand is looped around so that both strands are facing the same direction (ie: both strands are moving 3' to 5' to the right)
Telomerase can be used to replicate any missing parts.
Replication is bi-directional
Replication builds one strand 5' to 3' and the other from 3' to 5'
One strand is looped around so that both strands are facing the same direction (ie: both strands are moving 3' to 5' to the right)
Telomerase can be used to replicate any missing parts.
Explanation / Answer
Answer. One strand is looped around so that...
Let's take an an example of prokaryotic DNA replication. DNA polymerase III helps in the replication process.
The 2 strands are in the antiparallel direction. The template from 5 to 3 prime will synthesise the leading strand whereas, the template strand from 3 to 5 Prime will synthesise the lagging strand.
Now, the specificity of DNA polymerase III is that it can do synthesis only from 5 to 3 direction. Thus, the parent strand/template strand that has to form lagging strand forms a loop in form of sigma so that leading and lagging strand should be synthesized continuously from 5 to 3 prime.
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