Universal Codon of Life


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The Codons

All genes are composed of sequences of codons, which are triplets of nucleotide bases (A C G T/U). Ribosomes convert these sequences into proteins, which are polymers of amino acids.

Of the 64 possible codons, there are 20 amino acids coded for, 3 stop codons, and 1 start codon (the amino acid methionine). There are many redundant codons, which is important for protecting against transcription errors and mutations.

The Universal Codon of Life
First Base Second Base Third Base
U C A G
U UUU
phenylalanine
UCU
serine
UAU
tyrosine
UGU
cysteine
U
UUC
phenylalanine
UCC
serine
UAC
tyrosine
UGC
cysteine
C
UUA
leucine
UCA
serine
UAA
stop
UGA
stop
A
UUG
leucine
UCG
serine
UAG
stop
UGG
tryptophan
G
C CUU
leucine
CCU
proline
CAU
histidine
CGU
arginine
U
CUC
leucine
CCC
proline
CAC
histidine
CGC
arginine
C
CUA
leucine
CCA
proline
CAA
glutamine
CGA
arginine
A
CUG
leucine
CCG
proline
CAG
glutamine
CGG
arginine
G
A AUU
isoleucine
ACU
threonine
AAU
asparagine
AGU
serine
U
AUC
isoleucine
ACC
threonine
AAC
asparagine
AGC
serine
C
AUA
isoleucine
ACA
threonine
AAA
lysine
AGA
arginine
A
AUG
methionine
ACG
threonine
AAG
lysine
AGG
arginine
G
G GUU
valine
GCU
alanine
GAU
aspartate
GGU
glycine
U
GUC
valine
GCC
alanine
GAC
aspartate
GGC
glycine
C
GUA
valine
GCA
alanine
GAA
glutamate
GGA
glycine
A
GUG
valine
GCG
alanine
GAG
glutamate
GGG
glycine
G

Start & Stop codons

There is only one start codon, which is AUG. This is also the methionine amino acid.

There are three stop codons: UAA, UGA, UAG.

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