A control without DNA that ensures the reaction mix is not contaminated with template DNA is called a _______________ control?

A control without DNA that ensures the reaction mix is not contaminated with template DNA is referred to as a negative control. In molecular biology experiments, especially those involving polymerase chain reaction (PCR), it is crucial to confirm that any observed amplification is due to the presence of the intended template DNA.

The negative control contains all the components of the reaction mix—such as primers, nucleotides, and polymerase—except for the template DNA. This allows researchers to check for any contamination or nonspecific amplification that could lead to false-positive results. If the negative control shows amplification, it indicates that there is contamination in the reagents or the workflow.

Positive controls, on the other hand, contain a known template to ensure that the reaction conditions are suitable for amplification, while quality controls assess the overall reaction performance and reagents but do not specifically confirm contamination. Therefore, the negative control is essential for validating the integrity of the experimental setup by ruling out contamination.