RNA synthesis is facilitated by which of the following enzymes?
Multiple Choice
DNA polymerase
RNA polymerase
Transcriptase
mRNA synthase
The correct answer and explanation is:
The correct answer is RNA polymerase.
RNA synthesis, also known as transcription, is the process of copying a segment of DNA into RNA. This process is essential for gene expression and is facilitated by the enzyme RNA polymerase. RNA polymerase binds to the DNA at a specific region called the promoter and begins the synthesis of RNA by matching RNA nucleotides with their complementary DNA bases. The RNA strand is synthesized in a 5’ to 3’ direction, and once the RNA polymerase reaches a termination signal, it detaches from the DNA, releasing the newly formed RNA molecule.
RNA polymerase is distinct from DNA polymerase, which is responsible for synthesizing DNA during replication. While DNA polymerase also works to build nucleic acid strands, its role is focused on copying DNA, not synthesizing RNA. Transcriptase, as mentioned in the options, is sometimes used in the context of reverse transcription, where RNA is converted into DNA, but it is not involved in standard RNA synthesis from a DNA template. Similarly, mRNA synthase is not a commonly used term in molecular biology and does not refer to an enzyme responsible for RNA synthesis.
The process of RNA synthesis begins with initiation, where RNA polymerase binds to the promoter region of DNA. This is followed by elongation, during which RNA polymerase moves along the DNA, synthesizing a complementary RNA strand. Finally, termination occurs when the RNA polymerase reaches a termination sequence, signaling the end of RNA synthesis. The resulting RNA molecule may undergo further processing, including splicing and modification, before being used for protein synthesis. This entire process is critical for translating genetic information into functional proteins.