Question

The rate of transcription in a bacterium is 50 nucleotides/min and the average molecular weight of an amino acid is 110 Da. Time taken for synthesis of the mRNA of a protein with molecular weight of 110 kDa is min. (rounded off to one decimal place) Assume no abortive transcriptions and no sequences upstream of the start codon.

Answer 1

Correct Answer: 60

The goal is to determine the time required for the synthesis of an mRNA for a protein with a molecular weight of 110 kDa in a bacterium with a transcription rate of 50 nucleotides/min. 

1. First, calculate the number of amino acids present in the protein. Given the protein's molecular weight is 110 kDa and the average molecular weight of an amino acid is 110 Da, the number of amino acids is: \( \frac{110,000 \text{ Da}}{110 \text{ Da/amino acid}} = 1,000 \text{ amino acids} \).

2. The mRNA will require codons for each amino acid. Each codon consists of 3 nucleotides, so the total number of nucleotides required for 1,000 amino acids is: \( 1,000 \times 3 = 3,000 \text{ nucleotides} \).

3. Assuming no additional sequences, the mRNA transcript is simply the number of nucleotides that need to be synthesized, which is 3,000 nucleotides.

4. Given the transcription rate is 50 nucleotides/min, the time needed to transcribe 3,000 nucleotides is: \( \frac{3,000 \text{ nucleotides}}{50 \text{ nucleotides/min}} = 60 \text{ min} \).

5. Confirming the range provided: The calculated time (60 min) falls within the expected range of 60 to 60. Hence, the solution is correct and verified.

Therefore, the time taken for synthesis of the mRNA is 60.0 min.