DNA Translation (2024)

By Susha Cheriyedath, M.Sc.Reviewed by Michael Greenwood, M.Sc.

DNA translation is the term used to describe the process of protein synthesis by ribosomes in the cytoplasm or endoplasmic reticulum.

Image Credit: nobeastsofierce / Shutterstock

The genetic information in DNA is used as a basis to create messenger RNA (mRNA) by transcription. Single stranded mRNA then acts as a template during translation.

Ribosomes facilitate translation in the cytoplasm, by inducing the binding of complimentary transfer RNA (tRNA) anticodon sequences to the mRNA.

tRNAs carry particular amino acids, which are linked together by the ribosome. In this process, the mRNA is decoded to produce a specific amino acid chain, known as a polypeptide. Folding of the polypeptide creates an active protein, able to perform functions within the cell.

Cellular components involved in DNA translation

The key components required for translation are mRNA, tRNA, ribosomes, and aminoacyl tRNA synthetases. These four structures are briefly explained below:

Ribosome

The ribosome is a complex organelle, present in the cytoplasm, which serves as the site of action for protein synthesis. It provides the enzymes needed for peptide bond formation.

The nucleotide sequence in mRNA is recognized in triplets, called codons. The ribosome moves along the single strand mRNA, and when a complimentary codon sequence belonging to amino acid bearing tRNA bonds with the mRNA, the amino acid is added to the chain.

Messenger RNA (mRNA)

mRNA is used to convey information from DNA to the ribosome. It is a single strand molecule, complimentary to the DNA template, and is generated through transcription. Strands of mRNA are made up of codons, each of which signifies a particular amino acid to be added to the polypeptide in a certain order.

mRNA must interact with ribosomal RNA (rRNA), the central component of ribosomal machinery that recognizes the start and stop codons of mRNA, and tRNA, which provides the amino acid once bound with a complimentary mRNA codon.

Transfer RNA (tRNA)

This is a single strand of RNA composed of approximately 80 ribonucleotides. Each tRNA is read as a ribonucleotide triplet called an anticodon that is complementary to an mRNA codon. tRNA carry a particular amino acid, which is added to the growing polypeptide chain if complimentary codons bond.

Aminoacyl tRNA synthetases

These are enzymes that link each amino acid to their corresponding tRNA with the help of a two-step process. Each amino acid has a unique synthetase and the active site of each enzyme fits only one specific combination of the amino acid and tRNA.

Steps involved in DNA translation

There are three major steps in translation: initiation, elongation, and termination. These steps are briefly discussed below:

Initiation

Small ribosomal subunits bind to mRNA. The initiator tRNA which is equipped with the anticodon (UAC) also binds to the start codon (AUG) of the mRNA. The resulting large complex forms a complete ribosome and initiates protein synthesis.

Elongation

Following initiation, a new tRNA-amino acid complex enters the codon next to the AUG codon. If the anticodon of the new tRNA matches the mRNA codon, base pairing occurs and the two amino acids are linked by the ribosome through a peptide bond.

If the anticodon does not match the codon, base pairing cannot happen and the tRNA is rejected. Then, the ribosome moves one codon forward making space for a new tRNA-amino acid complex to enter. This process is repeated several times until the entire polypeptide has been translated.

Termination

As the ribosome moves along the mRNA, it encounters one of the three stop codons for which there is no corresponding tRNA. Terminator proteins present at the stop codon bind to the ribosome and trigger the release of the newly synthesized polypeptide chain.

The ribosome then disengages from the mRNA. On release from the mRNA, the small and large subunits of the ribosome dissociate and prepare for the next round of translation.

The polypeptide chains produced during translation undergo some post-translational modifications, such as folding, before becoming a fully active protein.

Translation

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FAQs

DNA Translation? ›

In biology, the process by which a cell makes proteins using the genetic information carried in messenger RNA (mRNA). The mRNA is made by copying DNA, and the information it carries tells the cell how to link amino acids together to form proteins.

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What is DNA transcription vs DNA translation? ›

DNA serves as the molecular basis of heredity through replication, expression, and translation processes. Replication creates identical DNA strands, while transcription converts DNA into messenger RNA (mRNA). Translation then decodes mRNA into amino acids, forming proteins essential for life functions.

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What is translation of DNA structure? ›

Translation of DNA. Translation is the process by which the genetic code contained within a messenger RNA (mRNA) molecule is decoded to produce a specific sequence of amino acids in a polypeptide chain.

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What reads DNA in translation? ›

As previously mentioned, ribosomes are the specialized cellular structures in which translation takes place. This means that ribosomes are the sites at which the genetic code is actually read by a cell. Ribosomes are themselves composed of a complex of proteins and specialized RNA molecules called ribosomal RNA (rRNA).

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What are the three steps of DNA translation? ›

Translation of an mRNA molecule by the ribosome occurs in three stages: initiation, elongation, and termination.

What are the 3 steps of translation? ›

Translation is generally divided into three stages: initiation, elongation, and termination (Figure 7.8). In both prokaryotes and eukaryotes the first step of the initiation stage is the binding of a specific initiator methionyl tRNA and the mRNA to the small ribosomal subunit.

How to translate DNA to RNA? ›

Transcription is the first step in gene expression. It involves copying a gene's DNA sequence to make an RNA molecule. Transcription is performed by enzymes called RNA polymerases, which link nucleotides to form an RNA strand (using a DNA strand as a template).

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Is DNA directly involved in translation? ›

During translation DNA is not directly involved in its process. DNA first gets transcribed to RNA to form the mRNA which then gets translated to form the amino acid chain. DNA is only used in the process of replication and transcription. In translation it has no direct role.

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How is DNA decoded? ›

The Information in DNA Is Decoded by Transcription.

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How many strands make up DNA? ›

Each molecule of DNA is a double helix formed from two complementary strands of nucleotides held together by hydrogen bonds between G-C and A-T base pairs.

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What amino always starts a protein? ›

This initiator tRNA always carries the amino acid methionine (in bacteria, a modified form of methionine—formylmethionine—is used) so that all newly made proteins have methionine as the first amino acid at their N-terminal end, the end of a protein that is synthesized first.

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