Final answer:
A codon is a sequence of three nucleotides that codes for a specific amino acid in protein synthesis, read from a 5' to 3' direction on mRNA. Codons play a crucial role in determining the structure of proteins based on the sequence encoded in DNA or RNA.
Step-by-step explanation:
A sequence of 3 nucleotides is called a codon, which codes for a specific amino acid during the process of protein synthesis. This concept is a fundamental aspect of molecular biology and genetics, explaining how proteins are constructed from instructions encoded in DNA and RNA. The genetic code is essentially a set of rules by which information encoded in the nucleotide sequences of DNA or RNA is translated into the amino acid sequences of proteins. It's essential to know that codons are read from a 5' to 3' direction on the mRNA strand.
Each codon corresponds to a particular amino acid, and the order of codons determines the primary structure of a protein. There are 64 possible codons, and most amino acids are encoded by more than one codon, making the genetic code redundant. This redundancy helps to protect against some types of mutations. Moreover, certain codons signal the start (AUG being the most common start codon) and stop (UAA, UAG, UGA) of the protein-coding sequence.