The human genome contains about 3 billion base pairs. During the first cell division after fertilization of a human embryo, S phase is approximately three hours long. Assuming an average DNA polymerase rate of 50 nucleotides/second over the entire S phase, what is the minimum number of origins of replication you would expect to find in the human genome?

If a DNA polymerase synthesizes in average 50 nucleotides/second, that means that in three hours (10800 seconds) it synthesizes about 540000 nucleotides.

However, if the human genome is composed of 3000000000 (3 billion) base pairs (nucleotids), the minimum number of DNA polymerases (working in the same number of origins of replication) to finish the duplication of all the genome in three hours is 5555,5. (3000000000/540000). As we know there is no half polymerase, so we round to 5556.

5556 molecules of DNA polymerases acting on 5556 origins of replication are needed.

luisvaschetto luisvaschetto · Answer 2 · 2022-04-08T13:21:38+02:00

The expected number of origins of replication in the human genome during DNA replication is equal to 2700.

What is the origin of replication?

An origin of replication is a region in the double helix of DNA that opens during DNA replication to allow the work of two DNA polymerases (one on each strand).

In this case, we know that the processivity of the DNA pol is equal to 10,800 seconds (3 hours) multiplied by 50 bases per second >> 540,000 base pairs (bp).

The human genome is 3 x 10⁹ bp in size, thereby the amount of DNA pols during DNA replication is equal to 3 x 10⁹ bp divided by 540,000 bp >> 5,500.

For each origin of replication it required two DNA pols (one for the leading strand and the other for the lagging strand), thereby the number of origin of replication is 5500/2 = 2750.

In conclusion, the expected number of origins of replication in the human genome during DNA replication is equal to 2700.

Learn more in:

https://brainly.com/question/21265857