Reverse Transcription and Retroviruses — NEET Biology
📚 Practice ConceptIn some viruses the flow of information is in reverse direction, that is, from RNA to DNA. Can you suggest a simple name to the process?
Which of the following statements correctly provides evidence or reasoning in support of the 'RNA world' hypothesis? S1: The existence of RNA molecules, such as ribozymes, that can catalyze biochemical reactions, demonstrates RNA's capacity for both genetic information and enzymatic function. S2: Essential cellular processes like metabolism, translation, and splicing are widely understood to have foundational evolutionary roots revolving around RNA. S3: In some viruses, RNA functions as the sole genetic material, illustrating its primitive capacity to store and transmit genetic information. S4: The intricate machinery for protein synthesis, including the structural and catalytic roles of ribosomal RNA (rRNA), is believed to have evolved primarily around RNA. S5: DNA's superior chemical stability and advanced repair mechanisms provided a selective pressure that led to its evolution from an earlier, more reactive RNA-based system.
View solution & NCERT explanation
Correct answer: C — S1, S2, S3, S4 and S5 are correct
The core concept tested is the evidence for the RNA world hypothesis. Let's evaluate each statement: S1: Ribozymes, which are RNA molecules that act as catalysts, are direct evidence for RNA's dual role as both an informational molecule and an enzyme, supporting the RNA world hypothesis. This statement is correct. S2: The NCERT text explicitly states that essential life processes (such as metabolism, translation, splicing, etc.) evolved around RNA. This statement is correct. S3: The fact that RNA acts as genetic material in some viruses (e.g., Tobacco Mosaic viruses) demonstrates its capacity to fulfill this role, providing support for its primitive function as genetic material. This statement is correct. S4: The protein synthesizing machinery evolved around RNA, and rRNA plays structural and catalytic roles during translation (e.g., 23S rRNA as a ribozyme in bacteria). This supports the central role of RNA. This statement is correct. S5: DNA's evolution from RNA with chemical modifications to become more stable (due to the lack of a 2'-OH group, presence of thymine, and double-stranded nature facilitating repair) is presented as a consequence of RNA's instability, thus supporting the transition from an RNA world. This statement is correct. All statements S1, S2, S3, S4, and S5 are correct. Incorrect options: A. Excludes S4 and S5 which are correct. B. Excludes S5 which is correct. D. Excludes S1 and S3 which are correct. The final answer is C. Recap: The RNA world hypothesis is supported by RNA's ability to act as both genetic material and catalyst (ribozymes), the evolution of key life processes around RNA, its role as genetic material in some viruses, and the subsequent evolution of more stable DNA from RNA.
What does NCERT say about some viruses flow information?
Has this concept appeared in NEET?
Which chapter is this from?
Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.
176/180MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.