HEREDITY
MUTATIONS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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it changes an amino acid in the encoded protein
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It has no effect on the amino acid sequence of the encoded protein
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it introduces premature stop codon into the mRNA
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it alters the reading frame of the mRNA
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Detailed explanation-1: -genetic mutations base substitution, called a “nonsense” mutation, results in a stop codon in a position where there was not one before, which causes the premature termination of protein synthesis and, more than likely, a complete loss of function in the finished protein.
Detailed explanation-2: -What is the effect of a nucleotide-pair substitution that results in a nonsense mutation in a gene? It introduces a premature stop codon into the mRNA.
Detailed explanation-3: -Thus, nonsense mutations occur when a premature nonsense or stop codon is introduced in the DNA sequence. When the mutated sequence is translated into a protein, the resulting protein is incomplete and shorter than normal. Consequently, most nonsense mutations result in nonfunctional proteins.
Detailed explanation-4: -A nonsense mutation refers to a base substitution in which the changed nucleotide transforms the codon into a stop codon. Such a change leads to a premature termination of translation, which can badly affect the formation of proteins.