Genetic code and amino acids

Examples of Integrated, Multi-set Concept Schemes (Annex 5)

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See other Examples of Integrated, Multi-set Concept Schemes. The concept scheme described here is discussed in the paper on: Patterns of N-foldness: comparison of integrated multi-set concept schemes as forms of presentation. This was prepared for a sub-project meeting of the Forms of Presentation group of the Goals, Processes and Indicators of Development (GPID) project of the United Nations University (UNU). The annexes were published in Patterns of Conceptual Integration. Brussels, UIA, 1984, pp. 161-204

The fundamental breakthrough in the biological sciences represents a valuable indication of the degree of patterning complexity which it is useful to consider. The information below is extracted from a number of sources

1.1 A single codon triplet contains the minimum information to specify an amino acid. Two amino acids are so specified: methionine, tryptophan

2.1 Two codon triplets are required for the specification of 90 of the amino acids

2.2 Two of the 20 amino acids are acidic (bearing a net negative charge): aspartic acid, glutamic acid 2 3 There are two sets of triplets which are used as terminators

2.4 For combinations of 3 (of the 4) genetic letters A, T (or U), C, and G to specify the 20 amino acids, each letter can be considered as specified by 2 digits of binary code in the 64 (i.e. 4 ) possibilities required to construct the code

2.5 In the helical structure of DNA. the four chemical bases ("letters")always link in pairs: A with T, and C with G . These links cross the helix, the sides being formed by sugarssand phosphates

3.1 Three (of the 4) genetic letters A, T (or U), C, and G are required to specify an amino acid, as the minimum information necessary: a codon triplet

3.2 Three of the codon triplets are used to define only one of the 20 amino acids: isoleucine

3.3 Three of the 20 amino acids are basic (bearing a net positive charge): lysine, arginine, histidine

4.1 The sequence of the genetic letters, A (adenine), T (thymine), C (cytosine), and G (guanine), in the DNA is first transcribed into the corresponding sentence of the letters A, U (uracil), C, and G in the messenger RNA. There are thus four possible elements from which the codon triplets can be constructed, the "words"

5.1 There are 5 of the 20 amino acids which are composed of 4 codon triplets: proline, threonine, alanine, valine, glycine

6.1 A codon triplet is defined by 6 positions of binary code in a set of 64 (4 ) elements _

6.2 There are 3 of the 20 aminoaclds which are composed of 6 codon triplets: serine, argin9ne, leucine

7.1 Seven of. the 20 amino acids are polar: glycine, serine, threonine, cysteine, tyrosine, aspargine, glutamine

8.1 Eight of the 20 amino acids must, in the case of man at least, be present in the diet and cannot be synthesized: methionine. tryptophan, threonine, valine, isoleucine, lysine, leucine, phenylalanine

8.2 Eight of the 20 amino acids are hydrophobic: alanine, valine, leucine, isoleucine, proline. phenylalanine, tryptophan, methionine

20.1 One or moreof the 64 possible codon triplets is required to construct each of the 20 amino acids essential to all forms of human life (as well as the 2 terminator codes)

64.1 (see 20.1)

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