School Science Lessons
2024-12-11
Please send comments to: j.elfick@uq.edu.au
(UNBiolGeneticCode)

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Genetic code
Contents

2.0.0 Amino acids, DNA codons

3.0.0 Nucleic acid, nitrogenous bases

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3.0.0 Nucleic acid, nitrogenous bases

A Adenine, 6-aminopurine, vitamin B4, (C5H5N5).

G Guanine, 2-​Amino-​6-​hydroxypurine, (C5H5N5O).

C Cytosine, 4-​Amino-​2-​hydroxypyrimidine, (C4H5N3O).

T Thymine (only in DNA), 2, 4-​Dihydroxy-​5-​methylpyrimidine, 5-Methyluracil, (C5H6N2O2).
or

U Uracil (only in RNA), 2, 4-​Dihydroxypyrimidine, 2, 4-Pyrimidinediol, (C4H4N2O2).

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2.0.0 Amino acids DNA codons
The code for a amino acid is a 3 letter codon.
Most amino acids have more than one codon, e.g. phenylalanine has TTT and TTC.
End of chain has 3 codons.
The first letter in a codon is in position 1,
The second letter in a codon is in position 2
The third letter in a codon is in position 3.
After position 3 is END of chain.

Alanine, DNA codons

Arginine, DNA codons

Asparagine, DNA codons

Aspartic acid, DNA codons

Cysteine, DNA codons

Glutamine, DNA codons

Glutamic acid, DNA codons

Glycine, DNA codons

Histidine, DNA codons

Isoleucine, DNA codons

Leucine, DNA codons

Lysine, DNA codons

Methionine, DNA codons

Phenylalanine, DNA codons

Proline, DNA codons

Serine, DNA codons

Threonine, DNA codons

Tryptophan, DNA codons

Tyrosine, DNA codons

Valine, DNA codons

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Amino acids and their 64 codons
The genetic code is the relation between a DNA codon and an amino acid.
Note that some amino acids are coded by several codons, e.g. Alanine, and some by only two codons, e.g. Asparagine, and some by only one codon, e.g.Methionine.
Ala Alanine GCT, GCC, GCA, GCG
Arg Arginine CGT, CGC, CGA, CGG, AGA, AGG
Asn Asparagine AAT, AAC
Asp Aspartic acid GAT, GAC
Cys Cysteine TGT, TGC
Gin Glutamine CAA, CAG
Glu Glutamic acid GAA, GAG
Gly Glycine GGT, GGC, GGA, GGG
His Histidine CAT, CAT
Ile Isoleucine ATT, ATC, ATA
Leu Leucine TTA, TTG, CTT, CTC, CTA, CTG
Lys Lysine AAA, AAG
Met Methionine ATG
Phe Phenylalanine TTT, TTC
Pro Proline CCT, CCC, CCA, CCG
Ser Serine TCT, TCC, TCA, TCG
Thr Threonine ACT, ACC, ACA, ACG
Trp Tryptophan TGG
Tyr Tyrosine TAT, TAC
Val Valine GUU, GUC, GUA, GUG
END of chain TAA, TAG, TGA
Position 1 is called the 5' end
Position 3 is called the 3' end

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AAA
AAC
AAG
AAT
ACA
ACC
ACG
ACT
AGA
AGG
ATA
ATC
ATG
ATT
CAA
CAG
CAT
CAT
CCA
CCC
CCG
CCT
CGA
CGC
CGG
CGT
CTA
CTC
CTG
CTT
GAA
GAC
GAG
GAT
GCA
GCC
GCG
GCT
GGA
GGC
GGG
GGT
GUA
GUC
GUG
GUU
TAA
TAC
TAG
TAT
TCA
TCC
TCG
TCT
TGA
TGC
TGG
TGT
TTA
TTC
TTG
TTT

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