Naming core promoter elements at -10 and -35 In bacterial genes, the DNA regions located approximately at -10 and -35 relative to the transcription start site are called:

Difficulty: Easy

Correct Answer: Promoters

Explanation:


Introduction / Context:
Bacterial transcription initiation relies on conserved promoter motifs. Recognizing these helps distinguish transcriptional from translational signals.



Given Data / Assumptions:

  • -35 and -10 elements are characteristic promoter regions.
  • They are recognized by sigma factor within the RNA polymerase holoenzyme.



Concept / Approach:
The -10 (Pribnow) and -35 hexamers define the core promoter in many bacterial genes, positioning polymerase and facilitating DNA melting. They are not translation or replication elements.



Step-by-Step Solution:
Identify the location: upstream of the transcription start site at defined negative positions.Associate those with promoter function and sigma recognition.Choose “Promoters.”



Verification / Alternative check:
Mutational changes to these motifs reduce initiation rate; compensatory sigma mutations can restore recognition, confirming promoter identity.



Why Other Options Are Wrong:

  • Start codons / Shine–Dalgarno: Translation signals on mRNA, not DNA promoter motifs.
  • oriC: The chromosomal origin of replication, unrelated to individual gene promoters.
  • Telomeres: Eukaryotic chromosome ends, absent in bacteria.



Common Pitfalls:
Confusing transcription initiation signals with translation initiation sequences.



Final Answer:
Promoters.


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