can anyone explain to me why the answer is b? how do you read it? The figure bel
ID: 22784 • Letter: C
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can anyone explain to me why the answer is b? how do you read it?
The figure below shows a portion of a gene and the corresponding mRNA and protein. Mutations b, c and d are base substitutions in which the base pair above the circle replaces the pair in the circle. Mutation 'a' is the addition of a base pair between the two A / T pairs as indicated by the arrow. Letter 'e' refers to the process of translating the mRNA base sequence into an amino acid sequence. Use the letters (a-e) and the universal genetic code to answer the questions 22-25 below. There is one answer to each question; individual letters can be used more than once, or not at all. Which letter below corresponds to the amino acid sequence caused by a frameshift in the DNA above? F-Y-R-E F-L-S-R F-Y F-Y-R-L None of the amino acid sequences are correctExplanation / Answer
H6 H7 H8 FLSR- TTYS LQELGA MGMG-DL LSAMFDFSEKLNS LALT EEELGLFTAVVL VSA----DR 548 For you knowledge. A frameshift mutation is a genetic mutation caused by a deletion or insertion in a DNA sequence that shifts the way the sequence is read. A DNA sequence is a chain of many smaller molecules called nucleotides. DNA (or RNA) nucleotide sequences are read three nucleotides at a time in units called codons, and each codon corresponds to a specific amino acid or stop signal. During translation, the sequence of codons is read in order from the nucleotide sequence to synthesize a chain of amino acids and form a protein. Frameshift mutations arise when the normal sequence of codons is disrupted by the insertion or deletion of one or more nucleotides, provided that the number of nucleotides added or removed is not a multiple of three. For instance, if just one nucleotide is deleted from the sequence, then all of the codons including and after the mutation will have a disrupted reading frame. This can result in the incorporation of many incorrect amino acids into the protein. In contrast, if three nucleotides are inserted or deleted, there will be no shift in the codon reading frame; however, there will be either one extra or one missing amino acid in the final protein. Therefore, frameshift mutations result in abnormal protein products with an incorrect amino acid sequence that can be either longer or shorter than the normal protein.
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