THE MOLECULAR BASIS OF INHERITANCE
DNA MAKES RNA MAKES PROTEIN
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Start Codons
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Stop Codons
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Promoter Regions
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Detailed explanation-1: -There are 3 STOP codons in the genetic code-UAG, UAA, and UGA. These codons signal the end of the polypeptide chain during translation. These codons are also known as nonsense codons or termination codons as they do not code for an amino acid.
Detailed explanation-2: -A stop codon is a sequence of three nucleotides (a trinucleotide) in DNA or messenger RNA (mRNA) that signals a halt to protein synthesis in the cell. There are 64 different trinucleotide codons: 61 specify amino acids and 3 are stop codons (i.e., UAA, UAG and UGA).
Detailed explanation-3: -Each three-letter sequence of mRNA nucleotides corresponds to a specific amino acid, or to a stop codon. UGA, UAA, and UAG are stop codons. AUG is the codon for methionine, and is also the start codon.
Detailed explanation-4: -The codons UAA, UAG, and UGA are the stop codons that signal the termination of translation.
Detailed explanation-5: -If the genetic code evolved before accurate nucleic acid replication, three stop codons allow the optimal spacing of open reading frames in primordial DNA or RNA genomes of random sequence [21].