After running a PCR reaction there multiple bands on an agar

After running a PCR reaction, there multiple bands on an agarose gel instead of a single band. Which step of the PCR reaction is the most likely source of the problem?

Denaturation

Annealing

Extension

What do the multiple bands on the gel suggest about the problematic PCR step?

Temperature too high

Temperature too low

Temperature at appropriate level

Solution

After running a PCR reaction, there multiple bands on an agarose gel instead of a single band. Which step of the PCR reaction is the most likely source of the problem?

Denaturation

Annealing

Extension

This is the second most step in PCR technique. In this step only our primer will go and bind with the template and start extending. If the temperature is low everything available will go and bind even small DNA. So due to this reason multiple banding will occur. If we increase the annealing temperature by 2-5° C then only it works. So this Annealing step of the PCR reaction is the most likely source of the problem.

What do the multiple bands on the gel suggest about the problematic PCR step?

Temperature too high

Temperature too low

Temperature at appropriate level

As explained above if the Annealing temperature is low only multiple bands appears. To avoid this 2-5 degree C has to be raised. And if the temperature is too high, primers cant bind to the template. TMoreover the temperature should not exceed the extension temperature.