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  1. 1-biological-molecules

    1-1-biological-molecules-carbohydrates
    11 主题
  2. 1-2-biological-molecules-lipids
    3 主题
  3. 1-3-biological-molecules-proteins
    5 主题
  4. 1-4-proteins-enzymes
    12 主题
  5. 1-5-nucleic-acids-structure-and-dna-replication
    8 主题
  6. 1-6-atp-water-and-inorganic-ions
    4 主题
  7. 2-cell-structure
    2-1-cell-structure
    7 主题
  8. 2-2-the-microscope-in-cell-studies
    4 主题
  9. 2-3-cell-division-in-eukaryotic-and-prokaryotic-cells
    8 主题
  10. 2-4-cell-membranes-and-transport
    7 主题
  11. 2-5-cell-recognition-and-the-immune-system
    7 主题
  12. 2-6-vaccines-disease-and-monoclonal-antibodies
    6 主题
  13. 3-exchange-and-transport
    3-1-adaptations-for-gas-exchange
    6 主题
  14. 3-2-human-gas-exchange
    10 主题
  15. 3-3-digestion-and-absorption
    5 主题
  16. 3-4-mass-transport-in-animals
    6 主题
  17. 3-5-the-circulatory-system-in-animals
    8 主题
  18. 3-6-mass-transport-in-plants
    6 主题
  19. 4-genetics-variation-and-interdependence
    4-1-dna-genes-and-chromosomes
    7 主题
  20. 4-2-dna-and-protein-synthesis
    6 主题
  21. 4-3-genetic-diversity-mutations-and-meiosis
    7 主题
  22. 4-4-genetic-diversity-and-adaptation
    6 主题
  23. 4-5-species-and-taxonomy
    4 主题
  24. 4-6-biodiversity
    9 主题
  25. 5-energy-transfers-in-and-between-organisms-a-level-only
    5-1-photosynthesis-a-level-only
    5 主题
  26. 5-2-respiration-a-level-only
    7 主题
  27. 5-3-energy-and-ecosystems-a-level-only
    9 主题
  28. 5-4-nutrient-cycles-a-level-only
    4 主题
  29. 6-organisms-respond-to-changes-in-their-environments-a-level-only
    6-1-response-to-stimuli-a-level-only
    12 主题
  30. 6-2-nervous-coordination-a-level-only
    10 主题
  31. 6-3-skeletal-muscles-a-level-only
    6 主题
  32. 6-4-homeostasis-a-level-only
    11 主题
  33. 7-genetics-populations-evolution-and-ecosystems-a-level-only
    7-1-inheritance-a-level-only
    6 主题
  34. 7-2-populations-a-level-only
    3 主题
  35. 7-3-evolution-a-level-only
    5 主题
  36. 7-4-populations-in-ecosystems-a-level-only
    7 主题
  37. 8-the-control-of-gene-expression-a-level-only
    8-1-genetic-mutations-a-level-only
    2 主题
  38. 8-2-regulation-of-gene-expression-a-level-only
    11 主题
  39. 8-3-using-genome-projects-a-level-only
    4 主题
  40. 8-4-gene-technologies-a-level-only
    13 主题
  41. exam-guidance-and-skills
    essay-guidance
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Uses of genetic fingerprinting

Forensic science

  • Crime scene investigations

    • DNA profiling has been used by forensic scientists to identify suspects of crimes

      • Samples of body cells or fluids (e.g. blood, saliva, hair, semen) are taken from the crime scene or victim’s body (e.g. victims of sexual abuse)

      • DNA is removed and profiled

      • The profile is compared to samples from the suspect (or criminal DNA database), the victim and people with no connection to the crime (control samples)

      • Care must be taken to avoid contamination of the samples

    • DNA profiling can also be used in forensics to identify bodies or body parts that are unidentifiable (e.g. too badly decomposed or parts remaining after a bomb blast)

  • Genetic fingerprinting is used in forensic science because each person (except identical twins) has a unique DNA profile, particularly in their VNTR regions

    • If the DNA pattern from a suspect matches the DNA found at the scene, it provides strong evidence that they were present

    • Conversely, a mismatch can exclude someone from suspicion

Crime scene investigation diagram showing DNA profiles and a comparison table for a victim and three suspects, with a question of identity.
DNA profiling in criminal investigations. Suspect 3 has the most fragments in common with the crime scene DNA so it is likely that they are the culprit.

Medical diagnosis

  • Detecting genetic disorders

    • DNA fingerprinting can identify disease-causing alleles or inherited conditions

    • E.g. Identifying alleles linked to Huntington’s disease, cystic fibrosis, or BRCA1/BRCA2 in breast cancer

  • Carrier screening

    • This process helps determine if a person is a carrier for a recessive genetic condition

  • Tissue typing

    • DNA fingerprinting is used before organ transplantation to check compatibility

  • Genetic fingerprinting is used because some diseases (e.g. Huntington’s, cystic fibrosis) are caused by specific mutations or patterns in the genome

    • By comparing a patient’s DNA to that of known affected individuals, scientists can detect the presence or absence of disease-causing alleles

    • It can also be used to predict disease risk or to guide treatment plans based on genetic profiles

Animal and plant breeding

  • Genetic fingerprinting can be used to:

    • ensure that selective breeding programs are effective

    • confirm parentage or pedigree in livestock and crops

    • maintain genetic diversity and reduce inbreeding

  • Genetic fingerprinting is used because breeders can confirm that offspring have inherited the correct genetic traits (e.g. high milk yield, disease resistance)

  • It helps identify unrelated individuals to maintain genetic diversity, which is important for the long-term health and productivity of a population

Examiner Tips and Tricks

You need to be able to explain why scientists might use genetic fingerprinting in the fields of forensic science, medical diagnosis, animal and plant breeding.