Translation (biology)
Ribosomes decode mRNA to assemble proteins from amino acids.
Translation is the biological process in which proteins are produced using RNA molecules as templates. It is a key stage of gene expression, performed by ribosomes, and involves decoding messenger RNA (mRNA) to synthesize a specific amino acid chain, or polypeptide, which later folds into an active protein.
- process
- Translation
- cellular_location
- Outside the nucleus (in ribosomes)
- key_molecules
- mRNA, tRNA, rRNA, ribosomes, aminoacyl tRNA synthetases
- stages
- Initiation, elongation, termination, recycling
- energy_requirement
- 4n-1 high-energy phosphate bonds for a protein of n amino acids
- rate_prokaryotic
- Up to 17–21 amino acid residues per second
- rate_eukaryotic
- Up to 6–9 amino acid residues per second
Lore & Background
Translation proceeds in four phases: initiation, elongation, termination, and recycling. Initiation involves the small ribosomal subunit binding to the 5' end of mRNA with initiation factors. In cap-dependent initiation, the ribosome binds initially at the 5' cap and then travels to the start codon. The first tRNA, carrying methionine, is attached at the start codon (AUG). The complete ribosome then commences elongation.
Reader's Guide
During elongation, the ribosome has two binding sites for tRNA: the aminoacyl (A) site and the peptidyl/exit (P/E) site. An incoming aminoacyl-tRNA binds to its complementary codon on the mRNA at the A site. A peptide bond forms between the amino acid of the tRNA in the A site and the amino acid of the charged tRNA in the P/E site, transferring the growing polypeptide chain to the tRNA in the A site. Translocation then moves the ribosome one codon toward the 3' end, powered by GTP hydrolysis. The process repeats until a stop codon is reached, leading to termination and release of the polypeptide. The genetic code—the matching from nucleotide triplets (codons) to specific amino acids—is universal and determines the protein sequence.
Did You Know?
- The ribosome is made up of two subunits: in eukaryotes, a small 40S subunit and a large 60S subunit.
- Transfer RNAs (tRNAs) are small noncoding RNA chains (74–93 nucleotides) that transport amino acids to the ribosome.
- Aminoacyl tRNA synthetases catalyze the bonding between specific tRNAs and their corresponding amino acids; mispairing can cause mistranslation.
- The rate of translation is significantly higher in prokaryotic cells (up to 17–21 amino acid residues per second) than in eukaryotic cells (up to 6–9 amino acid residues per second).
Frequently Asked Questions
Who is Translation (biology)?
Translation is the cellular process in which ribosomes read a messenger RNA strand and stitch together a specific chain of amino acids to build a protein. It serves as the final major step in gene expression, converting genetic instructions into functional molecules.
What are Translation (biology)'s powers/role?
Its core ability is decoding the nucleotide sequence of mRNA into a precise polypeptide chain, using tRNA adapters and rRNA within the ribosome. It proceeds through initiation, elongation, termination, and recycling, spending roughly 4n−1 high-energy phosphate bonds to assemble a protein of n residues.
Where does Translation (biology) operate?
Unlike transcription, translation takes place outside the nucleus, at ribosomes that are either free in the cytoplasm or tethered to the rough endoplasmic reticulum.
How does Translation (biology)'s story end?
The process concludes at a termination stage when a stop codon appears in the mRNA, prompting release factors to dislodge the finished polypeptide from the ribosome. The ribosomal subunits then dissociate and recycle to catch the next mRNA molecule.
Why is Translation (biology) important?
Without translation, the information encoded in DNA could never become the working proteins that drive virtually every cellular function. In prokaryotes it can crank out up to 17–21 amino acids per second, making it one of the fastest assembly lines in the cell.
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