A researcher starts with 5 molecules of a target double-stranded DNA and performs 6 cycles of polymerase chain reaction (PCR). What will be the final number of DNA molecules produced, and which organism is the source of the thermostable enzyme used in the extension step of this process?

Step-by-step solution

The number of DNA molecules produced after n cycles of PCR is given by the formula N₀ 2^n , where N₀ is the initial number of molecules. Given N₀ = 5 and n = 6 , the final number of molecules is 5 2^6 = 5 64 = 320 . The thermostable enzyme used in the extension step of PCR is Taq polymerase, which is isolated from the bacterium Thermus aquaticus. Agrobacterium tumefaciens is used as a cloning vector in plants, and Escherichia coli is a common host for cloning, not the source of Taq polymerase. Answer: 320 molecules