A gene and a codon are both fundamental concepts in genetics, but they serve different roles in the biological processes of living organisms.
Gene: A gene is a segment of DNA that contains the instructions for the synthesis of a specific protein or functional RNA molecule. Genes are the basic units of heredity and are passed from parents to offspring. Each gene is located at a specific position on a chromosome and can vary in length, often spanning thousands of base pairs. The sequence of nucleotides within a gene determines the sequence of amino acids in the protein it encodes, which in turn determines the protein’s function.
Codon: A codon, on the other hand, is a sequence of three nucleotide bases in DNA or RNA that corresponds to a specific amino acid or a stop signal during protein synthesis. There are 64 possible codons, each representing one of the 20 standard amino acids or a stop signal. Codons are the building blocks of the genetic code and are read by the ribosome during the process of translation to assemble proteins.
In summary, while a gene is a larger segment of DNA that contains the information needed to produce a functional product, a codon is a smaller unit within a gene that specifies a particular amino acid or a stop signal in the protein synthesis process.