The genetic code that specifies which protein will be made is determined by the sequence of nucleotides in DNA. Here are the key components involved:
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Nucleotides: The building blocks of DNA, which consist of a sugar, phosphate group, and a nitrogenous base (adenine, thymine, cytosine, or guanine).
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Gene: A segment of DNA that contains the instructions to produce a specific protein. The order of the nucleotides in a gene dictates the order of amino acids in the resulting protein.
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Transcription: The process where a specific segment of DNA (a gene) is transcribed into messenger RNA (mRNA). This involves the synthesis of RNA from the DNA template, where adenine pairs with uracil (in RNA) instead of thymine.
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Translation: The process where the information encoded in the mRNA is translated into a protein. This occurs in the ribosomes, where transfer RNA (tRNA) molecules bring amino acids to the ribosome in the order specified by the mRNA codons (three-nucleotide sequences).
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Codons: Each sequence of three nucleotides in the mRNA represents a specific amino acid or a stop signal (indicating the end of protein synthesis). The genetic code is universal among nearly all organisms, meaning the same codons generally specify the same amino acids.
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Regulatory Elements: In addition to the coding sequences, regulatory sequences in the DNA, such as promoters and enhancers, control when and how efficiently a gene is expressed, influencing the production of proteins.
Overall, the precise sequence of nucleotides in DNA determines the order of amino acids in proteins, and ultimately influences their structure and function.
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