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A fragment of DNA from chromosome 7 of each of two persons, Smith and Moore, are sequenced - VCE - SSCE Biology - Question 15 - 2012 - Paper 1
Question 15
A fragment of DNA from chromosome 7 of each of two persons, Smith and Moore, are sequenced. The nucleotide sequences in corresponding regions are shown below. This D... show full transcript
Worked Solution & Example Answer:A fragment of DNA from chromosome 7 of each of two persons, Smith and Moore, are sequenced - VCE - SSCE Biology - Question 15 - 2012 - Paper 1
Step 1
Step 2
B. the amino acid sequence in the polypeptides translated from the DNA of Moore and of Smith would be identical
Answer
Since Smith is unaffected and Moore has a genetic disorder, there is likely a difference in their DNA sequences that could affect the resulting amino acid sequence. Given that their DNA sequences differ in one nucleotide (Smith has G, Moore has A at the first position), this could lead to a different codon being read during translation, thus potentially altering the amino acid produced.
Hence, this statement is also incorrect.
Step 3
C. the mRNA transcribed from Smith’s DNA would have the sequence
Answer
The mRNA sequence is transcribed from the DNA template strand, replacing Thymine (T) with Uracil (U). For the sequence G A T G G A T C G A G G T C from Smith, the transcribed mRNA would be: A U A C C U A G C U C C A G.
Therefore, this statement is incorrect as the provided sequence does not match.
Step 4
D. Moore’s genetic disorder could be due to a deletion of one of the nucleotides.
Answer
Given the sequences, there is a mutation in Moore’s DNA that is absent in Smith’s DNA. The presence of a genetic disorder may indeed result from a deletion of one nucleotide, particularly affecting the production of the enzyme. The absence of a base sequence in Moore's DNA could lead to a dysfunctional enzyme, supporting the possibility of a deletion causing his genetic disorder.
Thus, this statement is correct.