Question

Which of the following is correct statement for RNA synthesis?
A. A single RNA polymerase can synthesize all types of RNA in prokaryotes
B. RNA polymerase II can synthesize mRNA in eukaryotes
C. A single RNA polymerase can synthesize all types of RNA in eukaryotes
D. RNA polymerase II can synthesize all types of RNA in prokaryotes
E. E. coli cell has only one type of RNA polymerase
Choose the correct answer from the options given below:

• A. A, B and E only
• B. A, B and C only
• C. B, C and E only
• D. B, C and D only

Hint:

Remember the mnemonic "R-M-T" for Eukaryotic RNA Polymerases I, II, and III. I = rRNA, II = mRNA, III = tRNA. Prokaryotes just have one enzyme for all!

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Transcription is the process of synthesizing RNA from a DNA template, catalyzed by RNA polymerase. The complexity of the transcription machinery differs significantly between prokaryotes and eukaryotes.

Step 2: Detailed Explanation:
- Statement A and E: In prokaryotes like E. coli, there is only one single type of RNA polymerase (core enzyme + sigma factor) that is responsible for the synthesis of all classes of RNA, including mRNA, rRNA, and tRNA. Therefore, statements A and E are correct.
- Statement B: In eukaryotes, there are three distinct RNA polymerases. RNA polymerase II specifically synthesizes mRNA (and some snRNAs). Pol I synthesizes rRNAs (except 5S), and Pol III synthesizes tRNAs and 5S rRNA. Thus, B is correct.
- Statement C: This is incorrect. Eukaryotes have multiple specialized polymerases, not just one.
- Statement D: This is incorrect. Prokaryotes have their own specific RNA polymerase; "RNA polymerase II" is a eukaryotic-specific term.
Combining the facts, A, B, and E are the correct scientific statements.

Step 3: Final Answer:
Prokaryotes use one polymerase for all RNA, while Eukaryotic Pol II is mRNA-specific. Correct Answer is Option 1.