Difference Between Genetic Code and Codon

Main Difference – Genetic Code vs Codon

Genetic code and codon are used in the storing of genetic information within the genetic material. The main difference between genetic code and codon is that genetic code is the set of rules used to store the genetic information within DNA whereas codon is a nucleotide triplet, which represents a specific protein. The genetic code is made up of codons. Genes carry specific information to produce a functional protein. During transcription, the genetic information of a gene is copied to messenger RNA (mRNA). The information in the mRNA is decoded during translation at the cytoplasm by ribosomes to make a functional protein. Each amino acid in the protein is represented by a specific codon in the sequence of the gene.

Key Areas Covered

1. What is a Genetic Code
      – Definition, Characteristics, Role
2. What is a Codon
      – Definition, Characteristics, Role
3. What are the Similarities Between Genetic Code and Codon
      – Outline of Common Features
4. What is the Difference Between Genetic Code and Codon
      – Comparison of Key Differences

Key Terms: Codon, DNA, Gene, Genetic Code, Messenger RNA (mRNA), Nucleotide Triplets, Protein, Transcription, Translation

What is a Genetic Code

Genetic code refers to the biochemical instructions by which genetic material stores the genetic information. It consists of 64 codons. Codons are nucleotide triplets, which represent specific amino acids. All codons except three are encoded for amino acids. Most amino acids are encoded by several codons. That means the genetic code is degenerate. But, each codon in the genetic code represents only one amino acid. Therefore, the genetic code is unambiguous.

The genetic code consists of three stop codons; UAA, UAG, and UGA. The AUG codon encodes for the amino acid ‘methionine’. It also serves as the start codon. Generally, genes store the information of proteins. During transcription, the genetic information in the DNA is encoded into a mRNA molecule. Typically, DNA is made up of four nucleotides: adenine (A), guanine (G), cytosine (C), and thymine (T). RNA consists of uracil (U) instead of thymine. Therefore, genetic code exists in two forms; genetic code with RNA nucleotides and genetic code with DNA nucleotides. The genetic code with RNA codons is shown in figure 1.

Figure 1: Genetic Code

The genetic code is identical in all species. However, a slightly different genetic code is found in mitochondrial DNA.

What is a Codon

A codon refers to a sequence of three DNA or RNA nucleotides, which represent a specific amino acid in a protein. All proteins are made up of 20 amino acids. Since there are 64 codons in the genetic code, each amino acid is represented by several codons. The coding sequence of a gene is made up of codons. During transcription, the nucleotide sequence of the sense strand is copied down on a mRNA molecule. This mRNA molecule is translated into a protein at the cytoplasm. The translation is facilitated by ribosomes. The correct amino acid for the synthesis of the polypeptide chain is carried by the transfer RNA (tRNA). The tRNA molecule contains the complement nucleotide sequence of the codon, which is called the anticodon. By the anticodon, tRNA can read the mRNA molecule and bring the correct amino acid.

Difference Between Genetic Code and Codon

Figure 2: Codons on a mRNA

Three codons serve as stop codons, which terminate the translation. The starting codon is always AUG in eukaryotes. Therefore, each protein in eukaryotes starts with methionine. A sequence of codons on a mRNA molecule is shown in figure 2.

Similarities Between Genetic Code and Codon

Both genetic code and codon are two methods used to store information within the genetic.
Both genetic code and codon are important to produce a functional protein.

Definition

Genetic Code: Genetic code refers to the set of rules by which genetic material stores genetic information.

Codon: Codon refers to three DNA or RNA nucleotides that represent a particular amino acid.

Correlation

Genetic Code: Genetic code is a collection of codons.

Codon: Codon is a nucleotide triplet, which represents an amino acid.

Amino Acids

Genetic Code: Genetic code contains codons, which represent each amino acid in a protein.

Codon: Codon represent a unique amino acid of a protein.

Conclusion

Genetic code and codon are two methods used to store genetic information in the genetic material. Genetic code is a collection of codons. It is made up of 64 different codons. Codon is a nucleotide triplet, which represents a specific amino acid. Three codons serve as stop codons, which terminate the translation. The codon, AUG serves as the start codon that initiates the translation. The main difference between genetic code and codon is the relationship between genetic code and codon.

Reference:

1.“Genetic code.” Encyclopædia Britannica, Encyclopædia Britannica, inc., 14 May 2013, Available here. Accessed 6 Sept. 2017.
2.“Codon.” Nature News, Nature Publishing Group, Available here. Accessed 6 Sept. 2017.