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Protein synthesis is the process by which the body creates proteins.
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Proteins consist of chains of amino acids, which amino acids used and their sequence determines each particular protein.
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The assembly of amino acids into proteins takes place in cells.
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The first stage, transcription, occurs in the nucleus.
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The second stage, translation, occurs in the cytoplasm.
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Transcription is the process of converting instructions for assembling a protein,
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located in the cell's DNA into messenger RNA. The template for building messenger RNA is a genetic sequence along a section of the DNA strand.
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Each strand of DNA contains nucleotides.
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with complementary bases.
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Adenine pairs with thymine and cytosine with guanine.
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Guanine.
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To start transcription, an enzyme called RNA polymerase attaches to the beginning of the DNA template.
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A sequence of three DNA bases called a base triplet contains information for assembling each amino acid of a protein.
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RNA polymerase reads the base triplets to build messenger RNA using free nucleotides.
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nucleotides.
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Corresponding messenger RNA triplets are called codons. In mRNA codons, uracil replaces thymine.
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thymine.
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Once the mRNA is built, certain enzymes remove introns, or sections that will not be used to build the protein. Enzymes splice the remaining ends or exons together.
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Then the functional mRNA leaves the nucleus.
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Translation is the process of using messenger RNA to assemble amino acids into a protein.
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The structure that will read the mRNA, called a ribosome,
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attaches to the mRNA strand.
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Initiated by a start codon, the ribosome reads each subsequent codon,
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which signals a transfer RNA molecule that has the matching anticodon sequence
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and specific amino acid.
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The process continues as additional transfer RNA molecules attach,
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bringing the correct amino acids to build the protein until the protein
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is completely assembled, signaled by the stop codon.
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codon.
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After the assembled protein breaks away from the ribosome,
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its subunits detach from the mRNA.
