AP BIOLOGY

Detailed explanation-1: -The extension step of the PCR where DNA polymerase gets into action happens at 72℃. This is in contrast to what we have learnt where enzymes are said to be functioning at the optimum temperature range of 35 to 40℃.

Detailed explanation-2: -During the extension step (typically 68-72°C) the polymerase extends the primer to form a nascent DNA strand. This process is repeated multiple times (typically 25-35 cycles), and because each new strand can also serve as a template for the primers, the region of interest is amplified exponentially.

Detailed explanation-3: -Extension: The temperature is increased to 72 °C, which is optimum for DNA polymerase activity to allow the hybridized primers to be extended.

Detailed explanation-4: -Final extension evaluation In this step, the PCR mixture is incubated at the extension temperature (generally 72°C) for a final 5–15 minute period.

Detailed explanation-5: -Step 3: Synthesis-the temperature is raised to 72’C to allow the DNA polymerase enzyme to synthesis of new strands of complementary DNA from free nucleotides in solution.