16. Regulation of Expression

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.

In a eukaryote, transcription factors called activators may stimulate gene expression by binding to DNA sites called __________.

Enhancers __________.

Dioxin, produced as a by-product of various industrial chemical processes, is suspected of causing cancer and birth defects in animals and humans. It apparently acts by entering cells and binding to specific proteins, which then enter the nucleus and alter the pattern of gene expression. Therefore, dioxin acts by mimicking the action of __________.

A high rate of gene transcription in eukaryotic cells is usually dependent on __________.

MyoD promotes muscle cell development by __________.

Which of these statements about enhancers is correct?a. They contain a unique base sequence called a TATA box.b. They are located only in 5′ untranslated regions.c. They are located only in introns.d. They are found both upstream and downstream from the transcription start site and are functional in any orientation.

Which of these statements about enhancers is correct?a. They contain a unique base sequence called a TATA box.b. They are located only in 5′ untranslated regions.c. They are located only in introns.d. They are found both upstream and downstream from the transcription start site and are functional in any orientation.

The functioning of enhancers is an example ofa. a eukaryotic equivalent of prokaryotic promoter functioning.b. transcriptional control of gene expression.c. the stimulation of translation by initiation factors.d. post-translational control that activates certain proteins.

In eukaryotes, what allows only certain genes to be expressed in different types of cells?

In eukaryotes, what allows only certain genes to be expressed in different types of cells?