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:
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:
Common Pitfalls:
Confusing transcription initiation signals with translation initiation sequences.
Final Answer:
Promoters.
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