Question

Which of the following statements are correct for a regulatory sequence in a gene?
(A). Provide signal that denote beginning of a gene.
(B). Provide signal that denote end of a gene.
(C). Influence transcription.
(D). Function as initiation point for replication.
Choose the correct answer from the options given below:

• A. (A), (B) and (C) only.
• B. (A), (B) and (D) only.
• C. (A), (B), (C) and (D).
• D. (B), (C) and (D) only.

Hint:

Gene expression regulatory sequences (promoters, enhancers, terminators) control transcription (making RNA from DNA), whereas replication origins control DNA replication (duplicating the genome).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Regulatory sequences are non-coding DNA segments that control gene expression by serving as binding sites for RNA polymerase and regulatory proteins.

Step 2: Detailed Explanation:
- Statement A is correct: Promoter regions are regulatory sequences that provide binding sites for RNA polymerase and transcription factors, signaling where transcription should begin.
- Statement B is correct: Terminator sequences are regulatory regions that signal the end of transcription, directing RNA polymerase to release the completed RNA transcript.
- Statement C is correct: Regulatory elements like enhancers and silencers bind transcription factors to increase or decrease the rate of transcription.
- Statement D is incorrect: The initiation point for DNA replication is the origin of replication (ori), which is a genome-replication feature rather than a gene-specific regulatory sequence controlling transcription.
- Therefore, only (A), (B), and (C) are correct.

Step 3: Final Answer:
The correct regulatory functions are represented by statements (A), (B), and (C) only.