Translation (biology)

In <a href="/facts/Biology/1M1ee3pB">biology</a>, translation is the process in living <a href="/facts/Cell_(biology)/bLM9UQvy">cells</a> in which <a href="/facts/Protein/Jxmagu3E">proteins</a> are produced using <a href="/facts/RNA/HxPeNfNj">RNA</a> molecules as templates. The generated protein is a sequence of <a href="/facts/Amino_acid/WDxYwBny">amino acids</a>. This sequence is determined by the sequence of <a href="/facts/Nucleotides/pQKEwlJI">nucleotides</a> in the RNA. The nucleotides are considered three at a time. Each such triple results in the addition of one specific amino acid to the protein being generated. The matching from nucleotide triple to amino acid is called the <a href="/facts/Genetic_code/zUK0bY1B">genetic code</a>. The translation is performed by a large complex of functional RNA and proteins called <a href="/facts/Ribosome/CF2u2gtg">ribosomes</a>. The entire process is called <a href="/facts/Gene_expression/alCPohLR">gene expression</a>.
In translation, <a href="/facts/Messenger_RNA/oUL6qxQn">messenger RNA</a> (mRNA) is decoded in a ribosome, outside the nucleus, to produce a specific <a href="/facts/Amino_acid/WDxYwBny">amino acid</a> chain, or <a href="/facts/Polypeptide/C4ltc7UG">polypeptide</a>. The polypeptide later <a href="/facts/Protein_folding/rf3nR2Y1">folds</a> into an <a href="/facts/Activation_energy/GqkgPvo0">active</a> <a href="/facts/Protein/Jxmagu3E">protein</a> and performs its functions in the cell. The polypeptide can also start folding during protein synthesis. The ribosome facilitates decoding by inducing the binding of <a href="/facts/Base_pair/xmPpPQ9W">complementary</a> <a href="/facts/Transfer_RNA/pR9T5XSl">transfer RNA</a> (tRNA) <a href="/facts/Anticodon/pR9T5XSl">anticodon</a> sequences to mRNA <a href="/facts/Codons/zUK0bY1B">codons</a>. The tRNAs carry specific amino acids that are chained together into a polypeptide as the mRNA passes through and is "read" by the ribosome.
Translation proceeds in three phases:

<ol><li>Initiation: The ribosome assembles around the target mRNA. The first tRNA is attached at the start codon.</li>
<li>Elongation: The last tRNA validated by the small ribosomal subunit (accommodation) transfers the amino acid. It carries to the <a href="/facts/Eukaryotic_large_ribosomal_subunit_(60S)/eULTb4Km">large ribosomal subunit</a> which binds it to one of the preceding admitted tRNA (transpeptidation). The ribosome then moves to the next mRNA codon to continue the process (translocation), creating an amino acid chain.</li>
<li>Termination: When a stop codon is reached, the ribosome releases the polypeptide. The ribosomal complex remains intact and moves on to the next mRNA to be translated.</li></ol>
In <a href="/facts/Prokaryotes/oYyvaDDH">prokaryotes</a> (bacteria and archaea), translation occurs in the cytosol, where the large and small subunits of the ribosome bind to the mRNA. In <a href="/facts/Eukaryotes/SkwyPLMA">eukaryotes</a>, translation occurs in the <a href="/facts/Cytoplasm/Wa0sE6xf">cytoplasm</a> or across the membrane of the <a href="/facts/Endoplasmic_reticulum/DVbLA7GE">endoplasmic reticulum</a> through a process called <a href="/facts/Protein_targeting/R3B37xMM">co-translational translocation</a>. In co-translational translocation, the entire ribosome–mRNA complex binds to the outer membrane of the <a href="/facts/Rough_endoplasmic_reticulum/DVbLA7GE">rough endoplasmic reticulum</a> (ER), and the new protein is synthesized and released into the ER; the newly created polypeptide can be immediately <a href="/facts/Secretion/VHk9eLAV">secreted</a> or stored inside the ER for future <a href="/facts/Vesicle_(biology_and_chemistry)/1KjHpjMM">vesicle</a> transport and secretion outside the cell.
Many types of <a href="/facts/Transcription_(biology)/bDgp9HDN">transcribed</a> RNA, such as tRNA, ribosomal RNA, and small nuclear RNA, do not undergo a translation into proteins.
Several <a href="/facts/Antibiotic/sF1kIfxg">antibiotics</a> act by inhibiting translation. These include <a href="/facts/Anisomycin/sxWsxo6m">anisomycin</a>, <a href="/facts/Cycloheximide/n4vb6su6">cycloheximide</a>, <a href="/facts/Chloramphenicol/4KQxQKvs">chloramphenicol</a>, <a href="/facts/Tetracycline/DQ0exP62">tetracycline</a>, <a href="/facts/Streptomycin/2zqL5HQb">streptomycin</a>, <a href="/facts/Erythromycin/dPt7avsU">erythromycin</a>, and <a href="/facts/Puromycin/sGp1Cb4p">puromycin</a>. Prokaryotic ribosomes have a different structure from that of eukaryotic ribosomes, and thus antibiotics can specifically target bacterial <a href="/facts/Infections/182XrncP">infections</a> without harming a eukaryotic <a href="/facts/Host_(biology)/L6mop0kh">host</a>'s cells.

Translation (biology) open-in-new

Translation (biology)