Why DNA Not RNA as Genetic Material — NEET Biology
📚 Practice ConceptAnswer to some of the questions such as, why DNA is the predominant genetic material, whereas RNA performs dynamic functions of messenger and adapter has to be found from the differences between chemical structures of the two nucleic acid molecules.
Which of the above statements regarding the differences between DNA and RNA are NOT correct? S1: DNA is chemically less reactive and structurally more stable than RNA, partly due to the absence of a 2'-OH group in its sugar. S2: Both DNA and RNA are typically double-stranded molecules with similar overall helical structures. S3: DNA contains the nitrogenous base thymine, while RNA contains uracil at the corresponding position. S4: RNA is exclusively involved in protein synthesis as a messenger, adapter, and structural molecule, never acting as genetic material. S5: While both DNA and RNA can mutate, RNA mutates at a slower rate due to its less labile nature, making it a better choice for long-term genetic information storage.
View solution & NCERT explanation
Correct answer: B — S2, S4 and S5
This question examines the key structural and functional differences between DNA and RNA, as well as their implications for genetic material. S1 is correct: The NCERT states, 'Further, 2'-OH group present at every nucleotide in RNA is a reactive group and makes RNA labile and easily degradable... Therefore, DNA chemically is less reactive and structurally more stable when compared to RNA.' The presence of thymine also adds stability. S2 is NOT correct: DNA is typically double-stranded, but RNA is usually single-stranded. While RNA can form secondary structures, it's not typically a double helix like DNA. S3 is correct: The NCERT explicitly states, 'Thymine is present in DNA. Uracil is present in RNA at the place of Thymine.' S4 is NOT correct: The NCERT mentions, 'RNA though it also acts as a genetic material in some viruses, mostly functions as a messenger. RNA has additional roles as well. It functions as adapter, structural, and in some cases as a catalytic molecule.' So, RNA can act as genetic material and has multiple functions, not exclusively involved in protein synthesis or never acting as genetic material. S5 is NOT correct: The NCERT states, 'In fact, RNA being unstable, mutate at a faster rate.' DNA is preferred for storage of genetic information due to its stability, implying RNA's higher mutation rate and lability make it unsuitable for long-term storage. Therefore, statements S2, S4, and S5 are NOT correct.
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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.
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