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