Answer:
The type of protein synthesized for each case of transcriptional control is given below:
a. Negative control in a repressible operon
Inactive repressor
b. Positive control in a repressible operon
Active activator
c. Negative control in an inducible operon
Active repressor
d. Positive control in an inducible operon
Inactive activator
Explanation:
Different types of operons exist in different bacterial systems and they control the transcription of genes by means of regulator proteins. These proteins are responsible for turning on or off the gene encoding a particuar protein depending on whether or not the cell requires for it.