The codon table is ordered in a really specific way. The sequence UCAG progresses along the first base, then the second, then the third. Does it occur exactly that way in nature, is it inspired by the way it occurs in nature, or is it totally arbitrary? I can’t find any information on this.
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I believe you are misunderstanding how a codon table works. A codon is a sequence of three base pairs (A, C, G, and T/U), or letters. No codon is ever four base pairs, always three. This is universal across all organisms and viruses, a codon is always three base pairs. The codon is read by the ribosome as corresponding to one of 20 different amino acids. So, let’s use [this](https://images.app.goo.gl/MqyTtfQdZQxnH1qz8) codon chart and read the codon UUC. The first base in the codon is U, so we start at the big U in the middle. The second letter is also a U, so we move from the U to the medium sized U, then to the last base of little C. This gives us the amino acid Phe (short for phenylalanine). Visually, you read UUC [like this](https://i.imgur.com/PDOB54T.jpeg)
Now, there are two things I want to point out. First, had the codon been UUA, that would give us Leu (leucine). This shows how each codon sequence is distinct and helps your body construct proteins in the proper way, as coded for by your DNA.
Second, see how the codon UUU would have also given us phenylalanine? This is called wobble, and helps keep some mutations silent, or having no effect, as a mutation of C (cytosine) into U (Uracil) means the same amino acid is still coded for.
Edited for clarity
The codon table is done by convention, we made the table since the the letter sequence can only make 64 possible combinations. It is ordered to provide ease of use.
The codon is determined by nature. Always three bases, each of 64 codons is read by the ribosomes but not translated until the start codon. This is conserved across species.
UAGC are the bases in mRNA. Codon is a combination of three bases.
Maybe I am misunderstanding your question. This is what we are understanding. Codon chart is made by people.
The three bases make a codon, the codons are determined by nature. They specify a amino acid, one codon to each amino acid, one start and if I remember correctly three stop. That is by nature, there are maybe some exceptions to the amino acids specified in specific cases but that is beyond my education (mitochondria maybe).
The organization of codon charts is based on the creator of the chart. There are circles within circles based on the first letter, second letter and third. There are charts and then if you do it enough you can memorize it.
Maybe you are asking this. How does the codon translate into a amino acid? Codon is nature.
The ribosomes “read” the mRNA for the start codon, after the start codon every three bases (codon) specifies a amino acids for a protein. Those sixty combinations code for an amino acid, the amino acid then is linked to the next and then the next until a stop codon is reached. Then the ribosome detached and the protein finishes folding and is done.
Maybe you are asking this. How did we get to a codon? Nature made it
DNA or RNA is copied. In the case of an organism with RNA, ribosomes just translate directly from the chromosome, they have UAGC as the bases. This is done with polymerase.
In DNA it needs to be translated to mRNA from TAGC to UAGC. This is using polymerase too.
In both cases ribosomes further translate the mRNA into amino acids to make proteins. The three bases do specify a amino acid, we have pictures of this and the current mRNA COVID-19 vaccine uses this.
Ribosomes are little machines, they fit the amino acids together because the bases have a tRNA attached to it that fit into the exposed UAGC spot inside the mRNA. The tRNA needs the ribosome to free the amnio acid and to attach them together.
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