Translation (biology)

Translation (Biology)

Overview of protein synthesis.

Translation is the process by which a cell converts the genetic information encoded in messenger RNA (mRNA) into a sequence of amino acids, ultimately producing a protein. This process is a key part of gene expression and occurs in the cytoplasm of both prokaryotic and eukaryotic cells.

Process of Translation

Translation involves several key steps: initiation, elongation, and termination.

Initiation

Initiation and elongation phases of translation.

The initiation phase begins when the small subunit of the ribosome binds to the mRNA. In prokaryotes, this binding occurs at the Shine-Dalgarno sequence, while in eukaryotes, it occurs at the 5' cap structure. The initiator transfer RNA (tRNA) carrying the first amino acid, usually methionine, binds to the start codon on the mRNA. The large ribosomal subunit then joins to form a complete ribosome, ready to begin protein synthesis.

Elongation

During elongation, the ribosome travels along the mRNA, reading its sequence in sets of three nucleotides called codons. Each codon specifies a particular amino acid, which is brought to the ribosome by a corresponding tRNA. The ribosome facilitates the formation of peptide bonds between the amino acids, extending the growing polypeptide chain.

Termination

Translation ends when the ribosome encounters a stop codon on the mRNA. Stop codons do not code for an amino acid but instead signal the release of the newly synthesized polypeptide chain. Release factors help disassemble the ribosome and free the completed protein.

Components Involved in Translation

Ribosome translating mRNA into a polypeptide chain.

Several key components are involved in the translation process:

• mRNA: Carries the genetic code from DNA to the ribosome.
• Ribosome: The molecular machine that facilitates the translation of mRNA into protein.
• tRNA: Transfers specific amino acids to the ribosome, matching the mRNA codon with the appropriate amino acid.
• Amino acids: The building blocks of proteins.

Regulation of Translation

Translation is tightly regulated to ensure proteins are synthesized at the right time and in the correct amounts. Regulation can occur at various stages, including mRNA stability, initiation factor availability, and ribosome activity.

Related Pages

• Transcription (biology)
• Gene expression
• Ribosome
• Protein folding

References

• Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., & Walter, P. (2002). Molecular Biology of the Cell. 4th edition. New York: Garland Science.
• Lodish, H., Berk, A., Zipursky, S. L., Matsudaira, P., Baltimore, D., & Darnell, J. (2000). Molecular Cell Biology. 4th edition. New York: W. H. Freeman.

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  Protein synthesis

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  Ribosome mRNA translation

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  Translation - Initiation & Elongation

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  Translation drawing by Carina Huerta

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  Protein translation

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  Model M0 of protein synthesis

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  Model M1 of protein synthesis