Question

The translocation rate of RNA polymerase II is 30 nucleotides per second for a gene you study that is 50,000 nucleotides in length. This gene contains 3 exons and 2 introns. The translocation rate of the ribosome on the resulting mRNA is also 30 nucleotides per second. Assuming that the translocation rates of RNA polymerase II and the ribosome are the rate limiting steps in their respective processes, which process (transcription or translation) do you expect to produce more product (mRNA or protein) over a 1-hour period? Explain your rationale.

Answer 1

Gene contains nucleotide=50,000 in number

As pre mRNA if formed which if RNA copy of total gene

Rate of translocation if RNA pol II = 30 nt/sec=30*60*60 nt per hour=108000­ nt/hr

With respect to mRNA formation=108000/50000=2.16 mRNA/hr

mRNA is processed to remove the introns

in gene 3/5 were exons then exon contained number of nt= 50,000*3/5= 30,000

and 30,000 nt are there to be translated

Rate of translocation of ribosomes= 30 nt/sec=30*60*60 nt per hour=108000­ nt/hr

With respect to protein formation=108000/30000=3.6 protein molecule/hr

So protein formation rate is higher than mRNA formation