Assume that instead of Taq polymerase, another polymerase, one that is very heat-sensitive, was used in a PCR. What differences would one observe when this new experiment is compared to the original experiment (one that includes Taq polymerase).

The heat sensitive polymerase would be denatured resulting in formation of little or no PCR products.

Explanation:

PCR is a technique that forms multiple copies of a small DNA sample. For the purpose, the DNA sample is exposed to very high-temperature conditions (around 95 degrees C) to facilitate the denaturation of DNA helix. These high-temperature conditions denature enzymes such as heat-sensitive DNA polymerases. Therefore, no or very little DNA molecules will be formed by the end of the process as the denatured DNA polymerase would not be able to extend the primers.

To avoid these conditions, heat-tolerant Taq polymerase is used in PCR which can withstand the extremely high-temperature conditions of PCR.