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In much the same way that nucleotides are the 'building blocks' of DNA, amino acids are the monomers that make up proteins. As mRNA is read, amino acids are chemically linked together to form polypeptides through a process called translation. 

 

 
How amino acids are chained together © 2013 DNA Learning Centre
Unlike DNA, in which there are only 4 types of monomer (C, G, A and T), there are 20 'proteinogenic' (protein-contributing) amino acids encoded in the standard genetic codeAn additional 2 amino acids also appear commonly in nature but require special mechanisms to be incorporated into polypeptides. Amino acids can vary greatly in their molecular size, electrostatic charge and chemical groups and this diversity contributes to the huge range of functions performed by proteins.

Each amino acid can represented by a three letter code e.g. Met = Methionine, Asp= Aspartic acid, or a single letter e.g. M = Methionine, D = Aspartic acid. A protein's peptide sequence is often written as a sequence of these single letters e.g. one of the polypeptide chains in insulin, a very small protein, is GIVEGCCTSICSLYGLENYCN 

In the form of proteins, amino acids comprise the second-largest component (water is the largest) of human musclescells and other tissues.

DNA Codons

DNA Codons © 2013 DNA Learning centre
Three letters of DNA Code e.g. CCT, code for one specific amino acid. These three-letter codes are called codons. The genetic code is traditionally represented as a RNA codon table due to the biochemical nature of the protein translation process. However, with the rise of computational biology and genomics, proteins have become increasingly studied at a genomic level. As a result, the practice of representing the genetic code as a DNA codon table has become more popular. Besides the 20 standard amino acids, there are more than 500 other amino acids found in nature.

Codon Tables

The DNA code shows redundancy, meaning several DNA triplets can code for the same amino acid. That's why there are codon tables and Nucleid Acid Notation Tables

Amino acid

DNA Codons

Ala/A

GCT, GCC, GCA, GCG

Arg/R

CGT, CGC, CGA, CGG, AGA, AGG

Asn/N

AAT, AAC

Asp/D

GAT, GAC

Cys/C

TGT, TGC

Gln/Q

CAA, CAG

Glu/E

GAA, GAG

Gly/G

GGT, GGC, GGA, GGG

His/H

CAT, CAC

Ile/I

ATT, ATC, ATA

Leu/L

TTA, TTG, CTT, CTC, CTA, CTG

Lys/K

AAA, AAG

Met/M

ATG

Phe/F

TTT, TTC

Pro/P

CCT, CCC, CCA, CCG

Ser/S

TCT, TCC, TCA, TCG, AGT, AGC

Thr/T

ACT, ACC, ACA, ACG

Trp/W

TGG

Tyr/Y

TAT, TAC

Val/V

GTT, GTC, GTA, GTG

  

STOP

TAA, TGA, TAG

START

ATG

© Text 2016 Wikipedia

 

Chemical Structure of 21 biological Amino Acids

© Image 2015 Wikipedia

 

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View full profile Jérôme Lutz from Berlin & Munich, Germany

I like to share the great things I discover daily while researching and working in the field of Synthetic Biology.

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I am a student at Cambridge University who has just finished a BA in Natural Sciences, focusing on Genetics in my third year. I am now studying for an MSc in Systems Biology.

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