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.

Verified step by step guidance

1. Identify the level at which the regulator is acting in the gene expression process. The problem states that the regulator controls the production of mRNA.
2. Understand the different types of gene expression control: Transcriptional control involves the process of transcribing DNA to mRNA, translational control involves the process of translating mRNA into protein, and post-translational control involves modifications after the protein has been made.
3. Analyze the statement that the regulator controls the production of mRNA. This indicates that the control is exerted at the stage of transcription, where mRNA is being synthesized from DNA.
4. Recall that transcriptional control is the regulation of the rate at which genes are transcribed to produce mRNA. It is the first level of gene expression control and determines which genes are expressed and when.
5. Conclude that since the regulator affects the production of mRNA, the control is at the transcriptional level, not at the translation or post-translation stages.

Key Concepts

Transcriptional Control

Transcriptional control refers to the regulation of gene expression at the transcription stage, where DNA is transcribed into mRNA. This process is crucial for determining which genes are expressed in a cell at any given time. In the context of the Hawaiian bobtail squid, the regulator molecule influences the production of mRNA for light-producing genes, indicating that these genes are controlled at the transcriptional level.

Gene Expression Regulation

Gene expression regulation encompasses the various mechanisms that cells use to increase or decrease the production of specific gene products, such as proteins. This regulation can occur at multiple stages, including transcription, translation, and post-translation. Understanding how the squid's light-producing genes are regulated helps explain how it can adapt its luminescence to avoid predation.

Luminescent Bacteria Symbiosis

The symbiotic relationship between the Hawaiian bobtail squid and Vibrio fischeri bacteria is a prime example of mutualism, where both organisms benefit. The bacteria provide bioluminescence, which the squid uses for camouflage, while the squid offers a nutrient-rich environment for the bacteria. This interaction highlights the importance of microbial partnerships in ecological adaptations and survival strategies.