Final answer:
A linear sequence of nucleotides that codes for a single polypeptide chain is known as a gene. Genes consist of DNA segments that undergo transcription and translation to form proteins.
Step-by-step explanation:
A linear sequence of nucleotides coding for a single polypeptide chain is known as a gene. Genes are segments of DNA (or RNA in some viruses) that carry the code for the synthesis of proteins or RNA molecules. The polypeptide chain itself forms the building block of a protein.
The process starts with the transcription of mRNA from DNA, which later serves as a template for translation, a process that converts the nucleotide-based genetic information into a protein product. Proteins are made up of amino acids, and the sequence of nucleotides in a gene dictates the specific order in which amino acids are assembled. This sequence is read in sets of three nucleotides called codons, with each codon corresponding to a specific amino acid.