The reaction mixture for PCR is missing the enzyme Taq polymerase. Which step of PCR would this affect?

The missing of Taq DNA polymerase will affect the DNA synthesis or polymerization step.

Explanation:

Taq DNA polymerase is also known as termostable DNA polymerase because it is able to exert its catalytic activity at high temperature.

Taq DNA polymerase is used for the 3rd step of polymerase chain reaction which deals with the joining of nucleotides by phosphodiester bond formation.

The missing or lack of Taq DNA polymerase will affect the DNA synthesis step of PCR.