UPSC Civil Services (Mains)
Chemistry optional
- 2 papers
- 250 marks each
- 3 h per paper
- 5 of 8 questions, Q1 and Q5 compulsory
Paper I covers physical and inorganic chemistry.
All topics
Paper I, physical and inorganic chemistry
Bio-inorganic chemistry: every question, 2021 to 2025
11 parts worth 105 marks have been set on this unit in UPSC CSE Chemistry Paper I from 2021 to 2025. Each one opens on its own page with the question, the answer in brief and the key points.
Syllabus
Metal ions in biological systems and their role in ion-transport across the membranes (molecular mechanism), oxygen-uptake proteins, cytochromes and ferredoxins.
Notes: Bio-inorganic chemistry: haemoglobin, cytochromes, Fe–S proteins (full notes) · short notes
2025
- Q5(e) Structure of [4Fe–4S] ferredoxin5 marks Answered
- Q7(a) T and R forms of haemoglobin15 marks Answered
- Q7(b) Cytochrome b, cytochrome c and cytochrome c oxidase5 marks Answered
2024
- Q6(c)(i) The sodium pump and its role10 marks Answered
- Q6(c)(ii) Bohr effect; role of cytochrome P45010 marks Answered
2023
- Q6(d) Rubredoxin and how it differs from ferredoxins10 marks Answered
- Q7(a) Haemoglobin and cytochrome c; oxy- and deoxyhaemoglobin10 marks Answered
2022
- Q5(c) Allosteric effect and homotropic modulators10 marks Answered
- Q8(b) Haemocyanin: active site, colours and functions10 marks Answered
2021
- Q5(c) Oxidation of haem to hematin, and how the protein prevents it10 marks Answered
- Q7(a) Iron–sulphur proteins: structures and redox states10 marks Answered
Printed copy and Kindle
UPSC Civil Services (Main) Chemistry Paper I: Model Answers 2021 to 2025
- All eight questions of each paper, with the question printed above its answer
- Question choice and time plan for each paper
- Topic-wise weightage and a topic-wise index