UPSC Civil Services (Mains), Chemistry optional · 2025 · Paper II
Q4(b)(iii). Salient features of the α-helix
Question
What are the salient features of alpha helix in regards to handedness, residues per turn and elongation per residue? What are the principal stabilizing factors for an alpha helix?
Model answer
The free solution for 2025 answers questions 1, 3, 5, 6 and 8, the ones picked in its time plan. Question 4 is answered in full in the Chemistry Paper II, 2021 to 2025 book, with every part of every paper.
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UPSC Civil Services (Main) Chemistry Paper II: Model Answers 2021 to 2025
- All eight questions of each paper, with the question printed above its answer
- Mechanisms drawn out and labelled on the scheme
- Topic-wise weightage and a topic-wise index
Coversα-helixprotein secondary structurehydrogen bondingPauling–Coreyresidues per turn
All parts of Question 4
- 4(a)(i) Molecular weight of poly(p-hydroxybenzoic acid)7 marks
- 4(a)(ii) Structure of the polymer3 marks
- 4(a)(iii) Precursor of natural rubber5 marks
- 4(b)(i) Nylon 6 and nylon 6,6 compared5 marks
- 4(b)(ii) Preparing syndiotactic polystyrene5 marks
- 4(b)(iii) Salient features of the α-helix5 marks
- 4(c)(i) Two dichlorides with NaN₃: neighbouring sulfur10 marks
- 4(c)(ii) Kinetic and thermodynamic enolates trapped with D₂O10 marks