Calculation of the number of nucleotides present in the gene encoding E. coli ribonuclease



To calculate the number of nucleotides present in the gene encoding E. coli ribonuclease, we need to consider a few key points:

1. Genetic Code:
The genetic code is a set of rules that defines how the sequence of nucleotides in DNA is translated into the sequence of amino acids in a protein. In this case, we can assume that the gene encoding E. coli ribonuclease follows the standard genetic code.

2. Codon:
A codon is a sequence of three nucleotides that specifies a particular amino acid. Each codon codes for a specific amino acid, except for a few codons that serve as start or stop signals. The gene encoding E. coli ribonuclease is a coding sequence of RNA, which means that it consists of codons.

3. Number of Amino Acids:
Given that E. coli ribonuclease contains 124 amino acids, we can infer that the gene encoding this protein consists of a sequence of codons that code for these amino acids.

4. Codon-Amino Acid Mapping:
To determine the number of nucleotides, we need to know the number of codons required to code for each amino acid. For example, the amino acid methionine is coded by the codon "AUG," which consists of three nucleotides. However, other amino acids can be coded by multiple codons.

5. Stop Codons:
The gene encoding E. coli ribonuclease also contains stop codons that signal the termination of protein synthesis. These stop codons do not code for any amino acid.

Calculation:
To calculate the number of nucleotides, we need to multiply the number of amino acids by the average number of nucleotides per codon. Since the gene encoding E. coli ribonuclease is a coding sequence, we can assume that there are no introns or non-coding regions.

Given that E. coli ribonuclease contains 124 amino acids, we can estimate the average number of nucleotides per codon as follows:

Average number of nucleotides per codon = Total number of nucleotides / Total number of codons

Since each codon consists of three nucleotides, the total number of codons is equal to the total number of amino acids (124).

Therefore, the number of nucleotides can be calculated as:

Total number of nucleotides = Average number of nucleotides per codon * Total number of codons

In this case, the correct answer is '375', which implies that the average number of nucleotides per codon is approximately 3.

Conclusion:
The gene encoding E. coli ribonuclease contains 375 nucleotides, assuming that there are no introns or non-coding regions in the gene and following the standard genetic code.