Question

DNA replication in early Drosophila embryos occurs about every 5 minutes. The Drosophila genome contains approximately 1.8 X 108 base pairs. Eukaryotic DNA polymerases synthesize DNA at a rate of approximately 60 nucleotides per second. Approximately how many origins of replication are required for this rate or replication?

Answer 1

20000 origins of replication are required for the rate of replication.

Step-by-step explanation:

The Drosophila genome size is 1.8x10⁸bp, then every strand has 1.8x10⁸nucleotides.

If the DNA polymerases synthesize DNA at a rate of 60 nucleotides. In one strand will be 30 nucleotides, thus, in 5 minutes:

5*60*30 = 9000

Then, the number of origins of replication is:

`OR=(1.8x10^(8) )/(9000) =20000`

Answer 2

5000 number of origins

Step-by-step explanation:

Drosophila genome contains =
`1.8 * 10^(8)` base pairs

Eukaryotic DNA polymerases synthesize = 60 nucleotides per second.

Note:DNA replication in people is bi directional.

Thus, by changing over the human DNA replication rate to the pace of drosophila replication, we get

Whereas, in 5 minutes we have 300 sec,

60 nucleotides

and

2 is bidirctional

300 sec × 60 × 2,

is equal to 36000/sec

Presently to show up at the quantity of sources of replication that is required for this pace of replication in drosophil, we need to separate as follows

rate of replication in drosophila/ rate of replication in human

= (
`1.8 * 10^(8)`) / 36000

=
`5 * 10^(3)`

= 5000 number of origins