Question

Bacteria and other microbes can be used to "clean up" an oil spill by breaking down oil into carbon dioxide and water. Two samples isolated from the Deepwater Horizon leak in the Gulf of Mexico were labeled A and B. The DNA of each was isolated and the percent thymine measured in each sample. Sample A contains 20.520.5 % thymine and sample B contains 30.730.7 % thymine. Assume the organisms contain normal double‑stranded DNA and predict the composition of the other bases.

Answer 1

In sample A,

The percentage of thymine or T is 20.5 %. A = T, so the percentage of A will also be 20.5 %.

Thus, A + T = 20.5 + 20.5 = 41 %

Therefore, G + C = 100 - 41 = 59 %

So, G = 59 /2 = 29.5 %

Also. G = C = 29.5 %

In sample B,

The percentage of Thymine or T is 30.7 %. As A = T, so A will also be 30.7 %.

Thus, A + T = 30.7 + 30.7 = 61.4 %

Also, G + C = 100 - 61.4 = 38.6 %

So, G = 38.6 / 2 = 19.3 %

Therefore, C will also be 19.3 %. As GC content is more found in the sample A, that is, 59 %. Hence, the sample A will possess the higher temperature to denature in comparison to B.