This application provides methods of detecting and quantitatively determining a target nucleic acid sequence in a sample, which comprise contacting the sample with a primer and a zymogene which encodes, but which itself is the anti-sense sequence of, a catalytic nucleic acid sequence, so that when the target is present, a single amplified nucleic acid molecule is produced which comprises the sequences of both the target and catalytic molecules. This invention further provides a method of simultaneously detecting the presence of a plurality of target nucleic acid sequences in a sample. Finally, this invention provides molecules and kits for practicing the instant methods.