The scientists used a radioactively labelled DNA probe to show that the cells of tobacco plant leaves contained the SUT1 gene - AQA - A-Level Biology - Question 6 - 2021 - Paper 3
Question 6
The scientists used a radioactively labelled DNA probe to show that the cells of tobacco plant leaves contained the SUT1 gene.
Describe how they would do this.
Do ... show full transcript
Worked Solution & Example Answer:The scientists used a radioactively labelled DNA probe to show that the cells of tobacco plant leaves contained the SUT1 gene - AQA - A-Level Biology - Question 6 - 2021 - Paper 3
Step 1
Extract DNA and Prepare Probe
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Initially, the scientists would extract DNA from the tobacco plant leaves using standard laboratory techniques, which may include cell lysis and purification methods. They would then label a DNA probe with a radioactive isotope that is complementary to the SUT1 gene sequence, ensuring the probe can specifically bind to the target DNA.
Step 2
Hybridization
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The labelled DNA probe would be mixed with the extracted tobacco DNA under controlled conditions, allowing for hybridization. This process involves the probe binding to its complementary sequence in the SUT1 gene, forming stable DNA:probe complexes.
Step 3
Separation and Detection
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After hybridization, the scientists would separate any unbound probes from the DNA samples using techniques such as washing or electrophoresis. Following this, they would use autoradiography or another imaging method to detect the radioactively labelled probes. This would show whether the SUT1 gene was present in the tobacco plant DNA.
Step 4
Analysis
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Finally, the intensity of the signal from the autoradiography would indicate the presence and amount of SUT1 gene. By analyzing these results, the scientists can confirm that the cells of tobacco plant leaves contain the SUT1 gene.
