How many nucleotides can be made by one DNA polymerase? Homework essay
2016 Genomics
Homework
How many nucleotides can be made by one DNA polymerase?
20141497
Chaeeun Lee
Abstract
DNA polymerases help to replicate the new DNA strand by adding matching nucleotide with the strand that can be used as a template. Then, how many nucleotides can be made by one DNA polymerase? I think it depends. However, we can estimate it by the number of origin of replication.
Introduction
During DNA replication, there are origins and from the origins, new strands are synthesized. In case of Okazaki fragment, it contains about 100~200 bps and it means one DNA polymerase synthesize 100 to 200 nucleotides. However, in case of leading strand, it is much longer than lagging strand. So by dividing whole genome number with origin of replication, we can find how many nucleotides can be made by one DNA polymerase.
Result
Before calculation, we should consider followings.
- Human has 3,234.83 Mb (Mega-base pairs) per haploid genome.
- At each cell division in humans, 30,000–50,000 DNA replication origins are activated. ->40000 in average, 20000 for haploid.
-Two strands for each DNA. We have to consider only one strand to find the length of nucleotide that can be made by one DNA polymer.
10000 replication origins (it means 20000/2strands).
By calculating (human genome base pair)/ (replication origin), it is 323483
Then, we have to divide it with 2 once more. It is because, from the replication origin, one direction is leading strand but the other is lagging strand.
-> <-
origin • – – – – – – – – – – – – – ——————————— • origin
Therefore, the answer is 161741.5 and it means one DNA polymerase can make about 161742 nucleotides.
Reference
https://en.wikipedia.org/wiki/DNA_polymerase
https://en.wikipedia.org/wiki/Human_genome
http://www.igh.cnrs.fr/equip/mechali/publications/RevieworiginsNRCMB2010.pdf
Campbell biology 7th edition, Reece, Taylor ,etc.
