DNA and RNA — Predicted 2026

AI-Predicted Question Angles for UPSC 2026

Based on trend analysis, current affairs, and recurring themes in DNA and RNA.

Impact of 2'-OH group on RNA stability and reactivity

high

This is a core chemical difference between DNA and RNA with significant biological implications. Questions often probe why DNA is more stable or why RNA is more reactive. Expect MCQs asking about the role of the 2'-OH group in alkaline hydrolysis or its absence contributing to DNA's role as a stable genetic material. This concept bridges chemistry (functional groups, hydrolysis) and biology (genetic information storage).

Quantitative application of Chargaff's Rules

high

Chargaff's rules (A=T, G=C) are a perennial favorite for numerical MCQs. Students might be given the percentage of one base and asked to calculate another, or the total purines/pyrimidines. These questions test basic arithmetic combined with fundamental knowledge of DNA structure. Expect variations that might involve calculating the number of hydrogen bonds if the base composition is known.

Identification of specific bonds and their locations

medium

Questions frequently ask to identify the type of bond linking a base to a sugar (N-glycosidic), sugar to phosphate (phosphodiester), or between complementary bases (hydrogen bonds). Understanding the chemical nature and location of these bonds is crucial. Expect diagrams or descriptive questions requiring precise identification of these linkages within a nucleotide or polynucleotide structure.

Functional roles of different RNA types in protein synthesis

medium

While more biological, the distinct roles of mRNA, tRNA, and rRNA are often tested. Questions might ask to match the RNA type with its function (e.g., 'carries genetic code' for mRNA, 'brings amino acids' for tRNA). This requires understanding the overall process of gene expression from a molecular perspective, which is often covered in chemistry chapters on biomolecules.