Samples of the tumour tissue and adjacent normal colon tissue were also sent to a biomedical researcher to investigate the genetic basis of the patient’s colorectal cancer. DNA was extracted from both the colorectal tumour tissue and the normal colon tissue using a silica column-based method. UV-Vis spectrophotometry was used to assess the concentration and purity of the extracted DNA. The spectrophotometric results for the colorectal tumour tissue are shown in Table 1.

Table 1. Spectrophotometric assessment of DNA extracted from colorectal tumour tissue.

Q2. Use the values provided in Table 1 to calculate the 260/230 and 260/280 absorbance ratios for the DNA extracted from colorectal tumour tissue. Evaluate whether each ratio falls within the expected range for pure DNA. If a ratio falls outside the expected range, identify the most likely contaminant. (2-3 sentences) (3 marks)