How Does DNA Code for Proteins in a Cell

DNA is the genetic material of most organisms. A DNA molecule is made up of a series of nucleotides. This nucleotide series represents the whole genetic information of the organism. The protein coding regions within the nucleotide series are known as genes. The information of a particular protein is coded by nucleotide triplets within the gene known as codons. Each nucleotide triplet represents a specific amino acid of the polypeptide chain. The whole set of codons is known as the genetic code, and it is used to code the information of a protein within a gene.

Key Areas Covered

1. What is Genetic Code
      – Definition, Characteristics
2. How Does DNA Code for Proteins in a Cell
     – Decoding the Genetic Code

Key Terms: Amino Acid, Codon, Genetic Code, Protein, Transcription, Translation

How Does DNA Code for Proteins in a Cell - Infographic

What is Genetic Code

The genetic code refers to the set of rules by which the genetic information is encoded within the genetic material. It defines how the four-letter code of DNA is translated into the twenty-letter code of amino acids. The amino acids are the building blocks of the proteins. Each amino acid is represented by a code of three nucleotides known as a codon. The genetic code that represents the 20 amino acids is shown in figure 1.

How Does DNA Codes for Proteins in a Cell

Figure 1: Genetic Code

64 codons are included in the genetic code, and 61 codons among them represent amino acids; the rest are stop codons. One of the characteristic features of the genetic code is its degeneracy. This means a single amino acid can be represented by more than one codon. Some other features of genetic code are:

  • genetic code does not overlap
  • a single nucleotide cannot be a part of two adjacent codons
  • the genetic code is nearly universal.

How Does DNA Code for Proteins in a Cell

Genes are elements of the genome that code for proteins. Genes are made up of a series of nucleotides. This nucleotide series represents a series of codons. Each codon represents a particular amino acid in the polypeptide chain. This codon series is transcribed into a mRNA during transcription and is decoded into an amino acid sequence of a functional protein during translation. The production of a protein by the use of genetic information in a gene is shown in figure 2.

How Does DNA Codes for Proteins in a Cell

Figure 2: Decoding the Genetic Code

Conclusion

The genetic information for proteins is encoded by the genes in the genome. The genes are made up of a series of nucleotides. These nucleotides are grouped into three resultant codons. Each codon represents a particular amino acid in the polypeptide chain of a protein.

Reference:

1. “Genetic code.” Nature News, Nature Publishing Group, Available here.
2. “How do genes direct the production of proteins? – Genetics Home Reference.” U.S. National Library of Medicine, National Institutes of Health, Available here.

Image Courtesy:

1. “06 chart pu3” By NIH –  (Public Domain) via Commons Wikimedia
2. “Genetic code” By Madeleine Price Ball- Own work (CC BY-SA 3.0) via Commons Wikimedia

About the Author: Lakna

Lakna, a graduate in Molecular Biology and Biochemistry, is a Molecular Biologist and has a broad and keen interest in the discovery of nature related things. She has a keen interest in writing articles regarding science.

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