General Studies 2022 GS Paper III 10 marks 150 words Compulsory Describe

Q6

Each year a large amount of plant material, cellulose, is deposited on the surface of Planet Earth. What are the natural processes this cellulose undergoes before yielding carbon dioxide, water and other end products? (Answer in 150 words) 10

हिंदी में प्रश्न पढ़ें

पृथ्वी की सतह पर प्रति वर्ष बड़ी मात्रा में वनस्पति पदार्थ, सेलुलोस, जमा हो जाता है। यह सेलुलोस किन प्राकृतिक प्रक्रियाओं से गुजरता है जिससे कि वह कार्बन डाइऑक्साइड, जल तथा अन्य अंत उत्पादों में परिवर्तित हो जाता है? (150 शब्दों में उत्तर दीजिए)

Evaluate your answer to this question → See all 2022 General Studies questions

Directive word: Describe

This question asks you to describe. The directive word signals the depth of analysis expected, the structure of your answer, and the weight of evidence you must bring.

See our UPSC directive words guide for a full breakdown of how to respond to each command word.

How this answer will be evaluated

Approach

The directive 'what are' demands a descriptive enumeration of natural processes. Structure as: brief introduction on cellulose abundance → sequential description of decomposition pathways (biological, chemical, thermal) → mention of end products → concise conclusion on ecological significance.

Key points expected

Biological decomposition: enzymatic hydrolysis by cellulase-producing bacteria (e.g., Cellulomonas, Trichoderma) and fungi in soil
Anaerobic digestion: conversion to methane and CO₂ by methanogenic archaea in wetlands, paddy fields, and rumen of herbivores
Aerobic respiration: complete oxidation to CO₂ and water via glycolysis, Krebs cycle, and ETC by decomposer microbes
Abiotic pathways: photochemical oxidation, combustion (forest fires), and slow thermal degradation
Formation of intermediate products: humus, lignin-cellulose complexes, and partial degradation products like cellobiose and glucose
Ecological significance: carbon sequestration in peatlands (e.g., Sundarbans) vs. rapid mineralization in tropical soils

Evaluation rubric

Dimension	Weight	Max marks	Excellent	Average	Poor
Demand-directive understanding	20%	2	Correctly interprets 'what are' as demanding process enumeration; covers both biological and abiotic pathways; addresses 'before yielding' implying sequential stages	Identifies some processes but misses either anaerobic/aerobic distinction or abiotic pathways; treats question as generic 'write about cellulose'	Misinterprets directive as asking for definition of cellulose or its structure; no process description; irrelevant content on synthetic cellulose or industrial uses
Content depth & accuracy	20%	2	Accurately names specific enzymes (cellulase, β-glucosidase), microbial groups, and biochemical pathways; correctly identifies end products for each process; mentions Indian ecosystems	Generic mention of 'bacteria and fungi decompose it' without naming enzymes or specific microbes; conflates aerobic and anaerobic outcomes	Scientifically incorrect statements (e.g., cellulose directly becomes CO₂ without intermediates); confuses cellulose with starch; omits water as end product
Structure & flow	20%	2	Logical sequence: deposition → biological degradation (aerobic/anaerobic) → abiotic routes → end products; clear paragraph breaks; maintains 150-word discipline	Some organization but jumps between processes without clear progression; either too brief or exceeds word limit significantly	Disorganized listing without coherence; no logical flow; fragmented sentences; grossly over/under word limit making evaluation difficult
Examples / case-law / data	20%	2	Cites specific Indian examples: paddy field methane emissions, termite gut symbionts, peatland carbon storage in Kashmir/Sundarbans, or forest fire data from FSI	Generic examples like 'forests' or 'soil' without specificity; or no examples despite question permitting them	No examples; or irrelevant examples (industrial paper production, human digestion); fabricated data or incorrect attribution
Conclusion & analytical edge	20%	2	Brief synthesis noting rate variation by climate (tropical vs. temperate), human impact on decomposition (stubble burning vs. natural decay), or carbon cycle significance	Generic concluding sentence like 'thus cellulose decomposes'; no analytical insight; mere summary of points	No conclusion; or conclusion contradicts body; irrelevant moralizing on environmental protection without connection to decomposition processes

Practice this exact question

Write your answer, then get a detailed evaluation from our AI trained on UPSC's answer-writing standards. Free first evaluation — no signup needed to start.

Evaluate my answer →