The three DNA stop codons are TAG, TAA, and TGA. These codons signal the end of protein synthesis during translation.
DNA Stop Codons Explained
DNA codons are sequences of three nucleotides that code for specific amino acids or stop signals during protein synthesis. While most codons specify an amino acid, three unique codons signal the end of the translation process. In DNA, these are:
- TAG
- TAA
- TGA
How Stop Codons Work
During translation, messenger RNA (mRNA) is read by ribosomes. When a ribosome encounters a stop codon on the mRNA, translation stops, releasing the newly formed polypeptide chain. It’s important to note that while these are the stop codons in DNA, their corresponding sequences in mRNA are different. The RNA stop codons are UAA, UAG, and UGA.
Differences Between DNA and RNA Stop Codons
The table below shows the stop codons in both DNA and RNA:
| Molecule | Stop Codons |
|---|---|
| DNA | TAG, TAA, TGA |
| RNA | UAA, UAG, UGA |
Key Points to Remember
- There are 64 possible codons.
- 61 codons code for amino acids.
- 3 codons are stop codons.
- DNA stop codons are not the same as RNA stop codons.
- Stop codons signal the end of translation, releasing the completed protein.
