Final answer:
Codons code for amino acids and are formed by three-nucleotide sequences in DNA or RNA. There are 64 possible codons, enough to encode the 20 amino acids found in proteins. Stop codons signal the termination of protein synthesis.
Step-by-step explanation:
What Do Codons Code For?
Codons in DNA code for amino acids which are the building blocks of proteins. The sequence of nucleotide bases (adenine A, cytosine C, guanine G, thymine T or uracil U in RNA) in a polynucleotide chain of DNA or RNA make up the genetic code. This genetic code is read in triplet codons, each consisting of three bases. With four different bases, there are 64 possible combinations of codons (4³), which are more than enough to encode all 20 amino acids used in proteins.
In the process of translation, each codon corresponds to a specific amino acid or a termination signal for protein synthesis. While 61 out of the 64 possible codons represent amino acids, three codons signal for the termination of protein synthesis, known as stop codons. The AUG codon has a dual role, coding for the amino acid methionine as well as serving as the initiation signal or start codon for protein synthesis.
Facts About the Genetic Code:
- Each codon is comprised of three nucleotides.
- The codon AAU codes for the amino acid asparagine.
- When a stop codon is reached during translation, it signals the end of protein synthesis.