The human β-globin polypeptide contains 146 amino acids. How many mRNA nucleotides are required to encode this polypeptide?

Verified step by step guidance

1. span>Step 1: Understand the relationship between amino acids and mRNA nucleotides. Each amino acid is encoded by a codon, which is a sequence of three mRNA nucleotides.
2. span>Step 2: Calculate the total number of codons needed for the β-globin polypeptide. Since the polypeptide contains 146 amino acids, you will need 146 codons.
3. span>Step 3: Determine the total number of mRNA nucleotides required. Multiply the number of codons (146) by the number of nucleotides per codon (3).
4. span>Step 4: Consider any additional nucleotides that might be required for the mRNA, such as start and stop codons, but for the purpose of this calculation, focus on the coding sequence.
5. span>Step 5: Conclude with the total number of mRNA nucleotides needed to encode the 146 amino acids of the β-globin polypeptide.

Key Concepts

Genetic Code

The genetic code is a set of rules that defines how the sequence of nucleotides in mRNA is translated into the sequence of amino acids in a protein. Each amino acid is encoded by a sequence of three nucleotides, known as a codon. Understanding this code is essential for determining how many nucleotides are needed to encode a specific polypeptide.

mRNA and Codons

mRNA, or messenger RNA, is a type of RNA that carries genetic information from DNA to the ribosome, where proteins are synthesized. Each codon in mRNA corresponds to a specific amino acid in the polypeptide chain. Since each amino acid is represented by a triplet of nucleotides, the total number of nucleotides required can be calculated by multiplying the number of amino acids by three.

Polypeptide Length and Nucleotide Calculation

The length of a polypeptide is determined by the number of amino acids it contains. To find the number of mRNA nucleotides required to encode a polypeptide, one must multiply the number of amino acids by three, as each amino acid is encoded by a triplet of nucleotides. Additionally, one must consider that the mRNA sequence does not include a stop codon in this calculation, as it is not part of the amino acid sequence.