Introduction to Molecular techniques

    • Molecular techniques is a core JC1 topic in H2 BIO. This topic extends from the topic DNA replication and protein synthesis by describing tools such as PCR, nucleic acid hybridization and gel electrophoresis that can yield valuable information. Such information can aid in the diagnosis of genetic diseases such as cancer.

    A selection of materials for molecular techniques

    Most common phrasing errors students commit during exams

    • Primers are complementary to the sequence to be amplified
    • Upon Southern blotting, 2 electrophoresis/radioactive bands appears

    Exam tips

    • Nucleic acid hybridization ≠ Southern blotting
    • In gel electrophoresis: if using EtBr, use UV light to visualize the band on the gel
    • When describing procedure for gel electrophoresis, write ‘direct current’ instead of current
    • When describing the PCR process, these words (denaturation, annealing, elongation/extension) should appear so as to demarcate each phase
    • In the advantages of PCR, sensitivity ≠ specificity. High sensitivity is requiring only a small amount of template/sample for amplification. High specificity is the ability to amplify only a specific region of DNA
    • In Southern blotting: if using radioactive probe, then autoradiography follows to visualize the bands by placing the blot over a photographic film so that the radioactivity on the bound probe can be exposed to the film to form an image. Ethidium bromide on the other hand is not suitable for visualization as there is no specificity to the target sequences.

    Questions and other matters

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