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Question 569
Genetics → General
Classification
Question
SSBAOptions
Explanation
Promoters are DNA regions to which RNA polymerase binds to initiate transcription. RNA polymerase produces a complementary RNA copy from the DNA sequence. This differs from translation, in which ribosomes use the mRNA sequence to direct polypeptide synthesis.
Option Validity
A) Enhancer sequences modify gene activity on the same chromosome; the DNA region identified by RNA-polymerase binding and transcription initiation is the promoter.
B) The promoter is correct, but helicases separate the strands of the DNA double helix. RNA polymerase is the enzyme that binds to the promoter to initiate transcription.
C) Exons contain information coding for protein or peptide sequences. This does not identify the promoter, and helicase is not the enzyme producing the complementary RNA copy.
D) Introns are intervening sequences within genes. They are not the promoter regions defined by RNA-polymerase binding and transcription initiation.
Further Reading
Saxena R. Textbook for MRCOG-1: Basic Sciences in Obstetrics and Gynaecology. 1st ed. Jaypee Brothers Medical Publishers; 2016. Chapter 8: Genetics — Deoxyribonucleic Acid; Process of Protein Synthesis — Transcription; Gene. Printed pages 254–255.