What Is the Genetic Code?

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Discussion Overview

The discussion revolves around the concept of the genetic code, specifically the relationship between nucleotide triplets and amino acids in proteins. Participants explore the definitions and implications of terms like "correspondences" and the distinction between DNA and RNA in this context.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions the meaning of "correspondences" in the context of the genetic code.
  • Another participant explains that nucleotide pairs are used because DNA is double-stranded, although a single strand can contain all necessary information.
  • A participant reiterates the question about the meaning of "correspondences."
  • It is noted that each triplet of nucleotides encodes a specific amino acid, with examples provided, such as UGU corresponding to Cysteine.
  • A participant points out that DNA contains thymine, not uracil, highlighting a distinction in the chart presented, which is based on RNA triplets.
  • Another participant acknowledges the conversion from DNA to RNA, clarifying that uracil replaces thymine during this process.

Areas of Agreement / Disagreement

Participants express differing views on the terminology and the implications of the genetic code, particularly regarding the use of nucleotide pairs versus triplets and the role of uracil in RNA versus thymine in DNA. The discussion remains unresolved with multiple perspectives presented.

Contextual Notes

There are unresolved questions about the definitions and implications of terms like "correspondences," as well as the stability and information storage in single versus double-stranded DNA.

Tyto alba
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According to https://www.ncbi.nlm.nih.gov/books/NBK21950/ and some other sources:

'Genetic code is the set of correspondences between nucleotide pair triplets in DNA and amino acids in protein.'

What dose correspondences mean in this regard?
I don't understand why nucleotide pair triplets and not simply nucleotide triplets?

P.S. I'm aware of codon and translation.
 
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Pairs simply because they are naturally stored as pairs (double-strand). A single strand is sufficient to have all the information, but it is less stable, and you need the pairing mechanism to copy it.
 
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And what dose correspondences mean in this regard?
 
Every triplet encodes a single amino acid. The sequence UGU "corresponds" to Cysteine, for example: If the DNA has this triplet, and it is translated, the cell will add Cysteine. UGC also corresponds to Cysteine. Here is a full diagram, to be read from the inside outwards.
 
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@mfb very good chart, wish I had one like it for teaching years ago.

But. DNA has thymine, not uracil. Uracil is the thymine 'analog' in RNA. So the nice chart is based on the triplets in RNA.
 
Ah, didn't think of the conversion. The chart is for RNA as the RNA is translated to amino acids. The DNA is translated to RNA before, with T->U.
 

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