1. In prokaryotes, the genes for metabolic pathways are ____ turned on and off as conditions change 2. . If an operon is regulated by ____ control, genes are ____ by a regulatory protein called a ____. positive; off unless they are switched on; repressor 3. How does RNA polymerase II bind to the DNA Transcription factors first bind to the promoter, then recruit RNA polymerase II. 4. Pepsin, a digestive enzyme that degrades proteins in the stomach, is synthesized as pepsinogen and converted to active pepsin in the stomach by the removal of several amino acids. The activation of pepsin is an example of ____ posttranslational regulation 5. An enhancer is a sequence that increases transcription of a gene ____. when it is located just upstream of the promote