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The genome of a small virus is depicted below, showing the positions of cutting sites (P and Q) for two restriction enzymes - VCE - SSCE Biology - Question 20 - 2008 - Paper 1
Question 20
The genome of a small virus is depicted below, showing the positions of cutting sites (P and Q) for two restriction enzymes. The length of DNA fragments obtained wh... show full transcript
Worked Solution & Example Answer:The genome of a small virus is depicted below, showing the positions of cutting sites (P and Q) for two restriction enzymes - VCE - SSCE Biology - Question 20 - 2008 - Paper 1
Step 1
Step 2
Calculate the combined lengths of fragments when both enzymes are used
Answer
When both enzymes are used together, the combinations of fragment lengths from EcoR1 (3 kB and 7 kB) and BamH1 (8 kB and 2 kB) will yield:
- 3 kB + 8 kB = 11 kB
- 3 kB + 2 kB = 5 kB
- 7 kB + 8 kB = 15 kB
- 7 kB + 2 kB = 9 kB
However, since we're asked for the lengths of the distinct fragments formed, we consider the shorter fragments that can occur from cutting at both sites.
Step 3
Identify the correct answer from the options provided
Answer
Given the possible lengths of 3 kB, 8 kB, 2 kB, and considering separate cuts leading to merged fragments, the distinct resultant lengths from dual cuts can be confirmed as 3 kB and 7 kB alongside BamH1's length yields a final resulting count. The correct answer corresponds to option D: 3, 7, 2.