DNA is composed of two strands, only one of which is typically used as a template for RNA synthesis.By what mechanism is the correct strand chosen?
A) The promoter acts to direct the RNA polymerase.
B) Only one strand has a start codon.
C) Both strands are tried, and the one that works is remembered.
D) An initiation factor informs the system about which strand to use.
E) The strand chosen randomly.

Question

Quizplus · Accepted Answer

The promoter region of DNA contains specific nucleotide sequences that act as binding sites for RNA polymerase. The RNA polymerase enzyme recognizes and binds to the promoter sequence, and then unwinds the DNA double helix to begin transcription. The promoter region is typically located upstream of the gene being transcribed, and its sequence determines which strand of DNA will serve as the template for RNA synthesis. Therefore, the correct strand is chosen based on the presence of promoter sequences that direct RNA polymerase to the appropriate strand of DNA.

DNA Is Composed of Two Strands, Only One of Which