Botany Optional Paper 2 Question Paper 2025 with Detailed Solution; Download PDF

UPSC Mains 2025 Question Paper for Botany Optional Paper 2 is available here to download in PDF Format. The exam has been conducted on August 31, 2025, in Afternoon Session (02:30 PM to 05:30 PM). This Paper comprises 8 questions which are of 250 marks. The duration of the exam is 3 hours.

UPSC Mains Botany Optional Paper 2 Question Paper 2025 with Detailed Solution; Download PDF (August 31, 2025)

Q1 (A) Write short notes in 150 words: Nuclear pore complex

Q1 (B) Write short notes in 150 words: Epistasis

Q1 (C) Write short notes in 150 words: Synaptonemal complex

Q1 (D) Write short notes in 150 words: Amphidiploidy

Q1 (E) Write short notes in 150 words: Lysosome

Q2 (A) What are the different methods of DNA sequencing? Elaborate the shotgun sequencing method.

Q2 (B) Describe the phenomenon of linkage by giving suitable examples. Why is the linkage an exception to Mendel's second law?

Q2 (C) Explain the structure and behaviour of B chromosomes in plants.

Q3 (A) Elucidate the molecular basis of sex determination in plants. Explain the role of homomorphic and heteromorphic sex chromosomes.

Q3 (B) Describe the structure of nucleosome and its role in DNA packaging.

Q3 (C) Explain in detail the various methods of plant hybridization.

Q4 (A) What is organic evolution? Discuss in detail the indirect evidences of organic evolution with suitable examples.

Q4 (B) Describe the structure of chloroplast with labelled diagram and write about its functions.

Q4 (C) Discuss in detail the role of mutations in plant breeding and crop improvement.

Q5 (A) Write short notes in 150 words:
Tests of significance

Q5 (B) Write short notes in 150 words:
Kranz anatomy and its significance

Q5 (C) Write short notes in 150 words:
Vernalization

Q5 (D) Write short notes in 150 words:
The IUCN Red List categories

Q5 (E) Write short notes in 150 words:
Endemism

Q6 (A) What are transgenic crops? Discuss the prospects and risks involved in their cultivation.

Q6 (B) What is biological nitrogen fixation? Explain the mechanism of symbiotic nitrogen fixation with examples.

Q6 (C) Describe the different forest types in India. Discuss in detail the crucial ecosystem services provided by these forests.

Q7 (A) What are the different gene transfer methods in plants? Give a brief account of direct gene transfer methods.

Q7 (B) What are the different carbon fixation pathways in plants? Discuss in detail the CAM pathway and its role in stomatal activity.

Q7 (C) What are the causes and consequences of global warming and climate change? Explain the approaches to deal with global warming.

Q8 (A) Define biodiversity. Explain the various ex situ and in situ methods of conserving biodiversity.

Q8 (B) What are phytohormones? Briefly discuss the role of auxin in plant growth and development. Explain its mechanism of action.

Q8 (C) Describe the various types of tropic movements in plants. Discuss their mechanism.

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