19.1. Principles of genetic technology
A subsection of Biology, 9700, through 19. Genetic technology
Listing 10 of 43 questions
In 1984, the geneticist Alec Jeffreys invented a DNA testing technique, known as DNA profiling, that produces a DNA banding pattern on a gel. The DNA banding pattern is unique to each individual. DNA profiling can be used in police forensic work to catch criminals. Since 1987, police in many countries have collected and stored DNA from crime scenes to create DNA profiles, which they try to match with the DNA profiles of criminal suspects. DNA at a crime scene may be obtained from hairs and traces of blood, semen and saliva. Explain why PCR may be needed before DNA from a crime scene can be profiled. Explain why electrophoresis produces a DNA banding pattern on a gel. GEDmatch is described as ‘an open data personal genomics website’. It can be used by people who want to upload their DNA data to trace their ancestors and other relatives. In 2018, police in the USA solved a large number of serious crimes. Some of these crimes had been unsolved for over thirty years. The police used GEDmatch to profile DNA taken from crime scenes and to look for matching DNA profiles. In many cases the police found partial matches to the relatives of criminals. This allowed the criminals to be identified and then charged on the basis of a complete DNA profile match. Suggest why the police strategy of comparing crime scene DNA with the GEDmatch database was so successful. Explain why GEDmatch is an example of bioinformatics. The first successful conviction resulting from the use of GEDmatch by the police was widely reported. Some journalists and broadcasters thought that the GEDmatch website should not have been used by the police in this way. In the days following the news, the number of citizens choosing to upload their DNA data to GEDmatch increased from 1500 to 5000 a day. Comment on the social and ethical issues raised by this first successful conviction.
9700_w21_qp_43
THEORY
2021
Paper 4, Variant 3
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The bacterium Escherichia coli divides once every 50 minutes at 36 °C. E. coli were grown on a medium containing only heavy nitrogen, 15N, until all of the bacterial DNA contained heavy nitrogen. Some of the bacteria were moved from a heavy nitrogen medium and cultured in a medium with only light nitrogen, 14N (0 minutes). These bacteria continued to reproduce and samples were extracted and centrifuged at regular intervals. Hybrid DNA contains both heavy and light nitrogen. The diagram shows the possible positions (upper, middle and lower) of the bands of DNA. The actual positions of bands in the first two samples are shown...
9700_w22_qp_13
MCQ
2022
Paper 1, Variant 3
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Use A husband and wife who already have a child with cystic fibrosis (CF) elected to have their second child tested for the condition while still a fetus in very early pregnancy. The results of the test, a DNA banding pattern, were discussed with a genetic counsellor. The relevant DNA banding pattern produced by electrophoresis is shown in . father first child fetus mother direction of movement of DNA fragments electrophoresis gel band of DNA With reference to , explain why, the fetus will develop CF, the positions of the bands of DNA of the first child and of the fetus indicate that the mutant allele for CF has a deletion in comparison with the normal allele. Explain briefly the need to discuss the result of the test with a genetic counsellor.
9700_w09_qp_41
THEORY
2009
Paper 4, Variant 1
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Questions Discovered
43