Final answer:
The nucleotide sequences of a gene that code for a protein are called exons. These sequences are spliced together to form the mRNA that specifies amino acid sequences in proteins. Three nucleotides make up a codon, which codes for a single amino acid.
Step-by-step explanation:
Nucleotide sequences of a gene that code for a protein are known as exons. In eukaryotic organisms, genes are composed of both exons and non-coding regions called introns. Exons are processed and joined together to form a continuous sequence that determines the structure of proteins, while introns are typically removed during RNA splicing.
In the context of genetics, a gene is a segment of DNA that carries the code for a specific polypeptide chain. This chain of amino acids then folds into a functional protein. Three consecutive nucleotides, known as a codon, code for a single amino acid, and the complete set of codons constitutes the genetic code.
Regulatory elements like promoters, operators, and repressors control the expression of these genes, determining when and how much of a protein is produced. The understanding of coding sequences and gene expression is pivotal in fields such as genetics, molecular biology, and biotechnology.