QUESTION 26 (4 marks)
a) State the three components of a DNA nucleotide.
[1 mark]
b) Describe the steps involved in DNA profiling.
[3 marks]
QCAA guide · typeset solution
QCAA sample response and mark allocation
26a) | Phosphate, deoxyribose sugar and a nitrogenous base. | • states phosphate, sugar and a base [1 mark] |
26b) | DNA samples are taken from two or more individuals and short sequences/STRs are identified and separated. The short fragments of DNA are then amplified using polymerase chain reaction (PCR). Results are compared by gel electrophoresis, so DNA similarities and differences between the samples and/or a known DNA profile can be determined. | • describes - one step [1 mark] - a second step [1 mark] - a third step [1 mark] |
QCAA sample response and marking criteria reproduced from the official guide.
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