Access the Amino Acid Codon Chart: Understand the Genetic Code

Replication, Transcription, and Translation – Meet the controller actions of life! Have you ever wondered how these events happening inside the microscopic cells of the living body define and control a whole being? 

The answer is Genetic code. The code is stored in DNA and RNA and translated into various chemicals responsible for the body’s various developments and functions.

Imagine this to be a secret message from one another where the actual words are replaced with letters and symbolized following a particular set of rules. This code is then decoded as it reaches the desired place, resulting in its expression. 

Let us explore the interesting basics of the genetic code, along with access to the amino acid codon chart that helps decode it.

The Genetic Code: What is a Genetic Code?

Proteins are formed by assembling amino acids in the proper order according to a set of instructions, which is in the genetic code. This code includes the nucleotide base sequence found in DNA and RNA. 

There are four nucleotide bases in DNA: Adenine (A), guanine (G), cytosine (C), and thymine (T). 

Transcription of DNA’s genetic code forms RNA. An RNA serves as a template for the production of proteins. 

There are four nucleotide bases in RNA: Adenine(A), guanine (G), cytosine (C), and Uracil (U). 

These genetic sequences or codes on the mRNA (messenger RNA that carries out this function) code for different amino acids, which combine to produce proteins. Every triplet nucleotide sequence is a codon that calls for an amino acid.

Know What a Codon is!

Codons are sequences of three DNA or RNA nucleotides, indicating amino acids or signaling protein synthesis, and are read by cells to decode mRNAs. There are 64 potential codons in all. Three of these are stop codons, which indicate the completion of protein synthesis, while the remaining 61 codons match the 20 distinct amino acids.

Start Codon

A start codon (such as AUG) initiates protein translation within mRNA molecules. In eukaryotes, AUG codes for methionine (Met) and in prokaryotes, AUG codes for formyl methionine (fMet). It marks the beginning of a protein strand synthesis. Initiation factors and tRNA are used to recognize start codons and initiate translation processes.

Note: In eukaryotes, AUG primarily initiates translation. However, in prokaryotes like E. coli, various codons, including AUG, GUG, and UUG, act as start codons.

Stop Codon

A start codon signals the termination of protein synthesis during translation. There are three stop codons: UAA, UAG, and UGA. These codons are also known as termination or nonsense codons. 

During translation, codons in an mRNA are read, starting at a start codon and going until a stop codon is reached. Methionine is located at the N-terminus of a protein, and the order of amino acids in that protein is specified by mRNA codons, which are read from 5′ to 3′.

From the Past:

Codon Discovery

Marshall Nirenberg and J. Heinrich Matthaei discovered the first codon in RNA through their poly-U experiment. They identified a three-uracil unit chain (UUU) as a code word for phenylalanine. Nirenberg and his team identified all 64 possible codons and their amino acids. In 1968, Nirenberg, along with Robert W. Holley and Har Gobind Khorana, was awarded the Nobel Prize in Physiology or Medicine.

20 Amino Acids Abbreviations

The 20 amino acids are listed here, along with their abbreviations:

1. A (Ala) – Alanine
2. R (Arg) – Arginine
3. N (Asn) – Asparagine
4. D (Asp) – Aspartic Acid
5. C (Cys) – Cysteine
6. Q (Gln) – Glutamine
7. E (Glu) – Glutamic Acid
8. G (Gly) – Glycine
9. H (His) – Histidine
10. I (Ile) – Isoleucine
11. L (Leu) – Leucine
12. K (Lys) – Lysine
13. M (Met) – Methionine
14. F (Phe) – Phenylalanine
15. P (Pro) – Proline
16. S (Ser) – Serine
17. T (Thr) – Threonine
18. W (Trp) – Tryptophan
19. Y (Tyr) – Tyrosine
20. V (Val) – Valine

What is an Amino Acid Codon Chart?

A reference source that collects distinct codons related to the amino acids they encode is a codon chart or table. Based on the nucleotide sequence, the chart aids in interpreting the genetic code and shows which amino acids are synthesized.

Given below is an easily understandable amino acid codon chart that will help you memorize them or refer to them whenever required.

Amino Acid	Codons
Alanine	GCU, GCC, GCA, GCG
Arginine	CGU, CGC, CGA, CGG, AGA, AGG
Asparagine	AAU, AAC
Aspartic Acid	GAU, GAC
Cysteine	UGU, UGC
Glutamine	CAA, CAG
Glutamic Acid	GAA, GAG
Glycine	GGU, GGC, GGA, GGG
Histidine	CAU, CAC
Isoleucine	AUU, AUC, AUA
Leucine	UUA, UUG, CUU, CUC, CUA, CUG
Lysine	AAA, AAG
Methionine	AUG
Phenylalanine	UUU, UUC
Proline	CCU, CCC, CCA, CCG
Serine	UCU, UCC, UCA, UCG, AGU, AGC
Threonine	ACU, ACC, ACA, ACG
Tryptophan	UGG
Tyrosine	UAU, UAC
Valine	GUU, GUC, GUA, GUG

Points to remember about the codon chart:

• The different codon combinations and the accompanying amino acids are shown in the codon chart.
• The genetic code is redundant or degenerate, as seen in the chart, which shows that a single amino acid can be coded by several codons.  

Conclusion

Knowing the codon is essential to understanding any amino acid when studying genetic code on a cellular level. Using this all-in-one amino acid codon chart sheet by Turito helps learners approach genetics with confidence and ease. 

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