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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
    3 主题
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Producing tissue cultures from cauliflower explants

  • Creating clones of cauliflowers is used to demonstrate totipotency through the production of tissue culture

    • Cauliflower is used because it is comprised mostly of actively dividing cells and can withstand being handled

  • Many plant cells are totipotent, unlike animal cells, and therefore, an entire plant can be reproduced from any of these cells

  • A small piece of the plant is cut, this is called an explant, which is then grown into a new clone of the original plant

  • The technique of using an explant is used by scientists to reproduce endangered species of plants

Apparatus

  • Disinfectant

  • Sterilising solution

  • Scalpel

  • Gloves

  • Forceps

  • Cauliflower

  • Agar growth medium containing a sterilant

  • Container

Method

  1. Wipe all surfaces with disinfectant and soak all apparatus in sterilant

    • It is important to ensure a sterile environment so that no fungi contaminate the experiment, which would result in seeing fungal growth rather than an explant growth

  2. Break off a small floret of cauliflower from the plant, then using a scalpel, cut a thin section of the floret (about 1cm long)

    • This thin section is the explant

  3. Sterilise the explant by soaking it in sterilising solution for 15 minutes, swirling the explant around within the solution every couple of minutes

    • This ensures that the explant is sterile and therefore only cauliflower cells are present

  4. Remove the explant using sterilised forceps and add it to a container of agar growth medium

    • The growth medium contains all the nutrients that the plant needs for growth, and also a sterilant to ensure no contamination occurs throughout the experiment

  5. Leave the container holding the agar growth medium and the explant on a sunny windowsill for three weeks

Results

  • The result of this experiment is to grow a cauliflower clone from an explant

  • This shows that the cells in the explant can produce all the different cell types that make up a full cauliflower plant, hence they are totipotent