The Best Description of the Initial Step in the Regulatory

question 55

Multiple Choice

The best description of the initial step in the regulatory process shown below is

• A) an sRNA is produced that can then be used to turn on genes.
• B) an sRNA is produced that can then be used to turn off genes.
• C) a sigma factor mRNA is transcribed and forms secondary structures at lower temperatures. When heated, the structures melt and the mRNA for the heat shock sigma factor, rpoH, can be translated.
• D) The hairpins contain codons for a needed amino acid. When amino acid is lacking, the ribosome stalls and prevents its formation, thus allowing translation.
• E) The hairpins contain codons for needed amino acids. When amino acid is present, the ribosome stalls and prevents the formation of hairpins, thus allowing translation.

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Definitions:

Regio-

A prefix indicating the region or position in a molecule where a chemical reaction occurs, often critical in determining the outcome of synthesis.

Meso Dibromide

A meso compound formed by the dibromination of an alkene, exhibiting optical inactivity due to internal symmetry.

(E)-Hex-3-Ene

A linear six-carbon compound with a double bond between the third and fourth carbons in the E (trans) configuration.

Enantiomeric Dibromides

Compounds that are mirror images of each other, each containing two bromine atoms attached to a carbon-based skeleton.