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One way to detect and measure accurately the amount of RNA in a tissue sample is by RT-PCR (reverse transcriptase-polymerase chain reaction) - AQA - A-Level Biology - Question 8 - 2017 - Paper 1
Question 8
One way to detect and measure accurately the amount of RNA in a tissue sample is by RT-PCR (reverse transcriptase-polymerase chain reaction). RT-PCR uses a reaction... show full transcript
Worked Solution & Example Answer:One way to detect and measure accurately the amount of RNA in a tissue sample is by RT-PCR (reverse transcriptase-polymerase chain reaction) - AQA - A-Level Biology - Question 8 - 2017 - Paper 1
Step 1
Step 2
Step 3
Explain why any DNA in the sample is hydrolyzed by enzymes before the sample is added to the reaction mixture.
Answer
The DNA must be hydrolyzed to remove any unneeded or contaminating DNA present in the sample. This is important because if DNA is present, it would compete with the template during amplification, potentially skewing the results.
Step 4
Use this information to calculate the ratio for RNA content in sample A : RNA content in sample B.
Answer
From Figure 9, determine the number of cycles needed for samples A and B to reach 50% maximum concentration of DNA (C). If sample A reaches this point at 15 cycles and sample B at 30 cycles, the ratio of RNA content can be calculated as follows:
[ ext{Ratio} = \frac{1}{C_A} : \frac{1}{C_B} = 15 : 30 = 1 : 2 ]
Thus the RNA content in sample A is half that in sample B.