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There were three suspects in an assault case - VCE - SSCE Biology - Question 5 - 2002 - Paper 1
Question 5
There were three suspects in an assault case. A forensic scientist found blood, other than the victim’s, at the site. DNA was extracted from five blood samples. - th... show full transcript
Worked Solution & Example Answer:There were three suspects in an assault case - VCE - SSCE Biology - Question 5 - 2002 - Paper 1
Step 1
a. Explain the role of the polymerase enzyme in PCR.
Answer
The DNA polymerase enzyme catalyzes the production of a new strand of DNA. Its primary role is to synthesize new DNA strands by adding nucleotides to a growing DNA chain during the PCR process. This is crucial for amplifying specific DNA sequences, allowing for the creation of multiple copies of the target DNA.
Additionally, the enzyme extends the DNA by pairing complementary bases with the original template strand, ensuring accurate replication.
Step 2
b. Name two properties of the DNA fragments which allow them to be separated from each other during gel electrophoresis.
Answer
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Charge: DNA fragments are negatively charged due to their phosphate backbone. When an electric current is applied during electrophoresis, these fragments migrate towards the positive electrode, allowing for separation based on charge.
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Size: The size of the DNA fragments affects their mobility through the gel matrix. Smaller DNA fragments can move faster and travel further than larger fragments, allowing for effective separation based on size differences.