Question

For questions 3 and 4, please remember that only one RNA strand is being synthesized, and only the template strand of the DNA is being transcribed.

3. (3 points) E. coli RNA polymerase adds ribonucleotides to an RNA strand at a rate of 22 per second. The size of the transcribed region of the largest gene in E. coli is 1538 bp. How long (in seconds) will it take RNA polymerase to complete transcription of an average-sized gene? (Round off to the nearest whole number):

Please show your calculations in the space below.

4. (4 points) The average size of the transcribed region in a human gene is 10,000 bp. If a eukaryotic RNA polymerase adds ribonucleotides at a rate of 28 per sec, how long (in minutes) will it take the RNA polymerase to complete transcription of an average human gene? (Round off to the nearest whole number):

Please show your calculations in the space below.

Answer 1

3. E. coli RNA polymerase adds ribonucleotides to an RNA strand at a rate of 22 per second. The size of the transcribed region of the largest gene in E. coli is 1538 bp. How long (in seconds) will it take RNA polymerase to complete transcription of an average-sized gene?

70 seconds.

22 ribonucleotides (bases) per second.

For 1,538 bases, it will be

1,538 22 = 69.91 seconds = 70 seconds

Approximately, 70 seconds are required to transcribe a gene of 1,538 bp at the rate of 22 bases per second.

Note: This is for the largest gene (1,538 bp). But for the average-sized gene, we can not answer with provided information. We need to know the size (bp) of average-sized gene.

4. The average size of the transcribed region in a human gene is 10,000 bp. If a eukaryotic RNA polymerase adds ribonucleotides at a rate of 28 per sec, how long (in minutes) will it take the RNA polymerase to complete transcription of an average human gene?

6 minutes.

28 ribonucleotides (bases) per second.

For 10,000 bases, it will be

10,000 28 = 357.14 seconds = 5.95 minutes (357.1460).

Approximately, 6 minutes are required to transcribe a gene of 10,000 bp at the rate of 28 bases per second.