16. Regulation of Expression

Compare and contrast the items in each pair: (c) general transcription factors and sigma.

Compare and contrast the items in each pair: (a) enhancers and the E. coli CAP binding site

Compare and contrast the items in each pair: (b) promoter-proximal elements and the operator of the lac operon

Compare and contrast the items in each pair: (c) general transcription factors and sigma.

Compare and contrast the items in each pair: (a) enhancers and the E. coli CAP binding site

Compare and contrast the items in each pair: (b) promoter-proximal elements and the operator of the lac operon

In the follow-up work to the experiment shown in Figure 19.6, the researchers used a technique that allowed them to see if two DNA sequences are in close physical proximity (association). They applied this method to examine how often an enhancer and the core promoter of the Hnf4a regulatory gene were near each other. A logical prediction is that compared with rats born to mothers fed a healthy diet, the Hnf4a gene in rats born to mothers fed a protein-poor diet woulda. show no difference in how often the promoter and enhancer associated. b. never show any promoter–enhancer association.c. show a lower frequency of promoter–enhancer association.d. show a higher frequency of promoter–enhancer association.

The Hawaiian bobtail squid (Euprymna scolopes) is able to glow from luminescent Vibrio fischeri bacteria held in its light organs. As it swims at night near the ocean surface, it adjusts the amount of light visible to predators below to match the light from the stars and moon. Predators have difficulty seeing the illuminated squid against the night sky. The bacteria glow in response to a molecule that regulates expression of genes involved in light-producing chemical reactions. The regulator controls production of the genes' mRNA. Therefore, the light-producing genes are undera. transcriptional control.b. translational control.c. post-translational control.d. negative control.