At this juncture it would be useful to emphasize that of the 20 Amino Acids found in protein, nine are “essential” and 11 are classified as “non-essential”. The nine are considered essential because they cannot be produced within the human body, whereas the remaining 11 are classified as non-essential due to the fact that they can be synthesized by the body from the essential Amino Acids. There are additional Amino Acids, not part of protein, as well. (Smolin & Grosvenor, 1994).
|
Essential Amino Acids |
Non-essential Amino Acids |
|
Histidine |
Alanine |
|
Isoleucine |
Arginine |
|
Leucine |
Asparagine |
|
Lysine |
Aspartic Acid |
|
Methionine |
Cysteine |
|
Phenylalanine |
L-Glutamic Acid |
|
L-Threonine |
Glutamine |
|
L-Tryptophan |
Glycine |
|
Valine |
L-Proline |
|
|
Serine |
|
|
Tyrosine |
|
Some other Amino Acids, not part of Protein |
|
|
Carnitine |
|
|
Hydroxyproline |
|
|
Ornitine |
|
|
Taurine |
|
Once again, when a number of nucleotides, in a particular sequence (each represented by a unique Codon) are strung together, a polynucleotide results. A more distinct name for a given polynucleotide is a certain Amino Acid, regardless of which Codon may be employed to state its precise sequence of nucleotides.
Review: 1) The same combination of nucleotides may represent more than one Amino Acid.
2) Different combinations of nucleotides may represent the same Amino Acid.
3) It is therefore the precise sequencing of the particular combination polynucleotide components that gives rise to one Amino Acid or another.
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