Which amplification procedure uses RNA polymerase as a critical component?

The amplification procedure that uses RNA polymerase as a critical component is the Q beta replicase method. This process involves the replication of RNA using the Q beta bacteriophage's replicase enzyme, which is an RNA-dependent RNA polymerase. In this context, the polymerase synthesizes new RNA strands complementary to the original RNA template.

This method is particularly valuable in applications where amplification of RNA sequences is desired, allowing for the production of many copies of a target RNA rather than relying solely on DNA amplification techniques. The unique aspect of Q beta replicase is its ability to amplify RNA directly, unlike many other amplification techniques that primarily focus on DNA.

In contrast, other amplification methods, such as real-time PCR and ligase chain reaction, rely on DNA polymerases or ligases rather than RNA polymerases. Strand displacement amplification also primarily focuses on DNA amplification through a mechanism that does not involve RNA polymerase. Thus, Q beta replicase stands out as the amplification procedure that utilizes RNA polymerase, making it the correct answer.