Given that the rate of DNA synthesis of a plasmid in yeast is 50 nucleotides per second and the circular plasmid replicates in 20 minutes, what is the approximate maximum size of the plasmid?
A)30,000 bp
B)60,000 bp
C)120,000 bp

Question

Quizplus · Accepted Answer

1 minute = 60 seconds, so 20 minutes = 20 x 60 = 1200 seconds of DNA synthesis. 
At a rate of 50 nucleotides per second, the plasmid would have synthesized approximately 50 x 1200 = 60,000 nucleotides or base pairs (bp). 
Since DNA is double-stranded, the actual size of the plasmid would be roughly twice this amount or 120,000 bp. 
Therefore, the best choice is B.

Given That the Rate of DNA Synthesis of a Plasmid