In IB Biology HL D1.1.4, review how PCR uses primers, temperature cycles and Taq polymerase to amplify selected DNA, and how gel electrophoresis separates DNA fragments by size and charge.
The surface antigen gene of hepatitis B virus (HBsAg) was cloned into plant cells using Agrobacterium tumefaciens. Plant cells were selected according to their resistance to kanamycin.
Transformed plant cells were analysed by PCR to see whether they contained the HBsAg gene of 681 base pairs (bp). The image shows the resulting electrophoretic gel with lane 1 showing the reference ladder (size markers), lane 2 a positive control and lane 3 a negative control. Lanes 4 and 5 show the PCR amplification of genomic DNA from transformed plant cells.
Using the electrophoretic gel image, deduce with a reason whether the plant cell transformation was successful.