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Topic Fermentation
Asked 4 times across 4 UPSC exams over 42 years (1981–2023), peaking in 2014.
Key insights
- Most tested in CSE — 1 of 4 PYQs
- Most asked in 2014
- Recurs across 3 years (1981–2023)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
CSE 1981 → CAPF 2014 → CDS 2014 → NDA 2023
How the concept evolved
Long-running — most appearances (3 of 4) predate 2016, and it still returns.
Related concepts
Ideas UPSC tests alongside this one — keep exploring.
Sample questions
You've seen the pattern — here are a few of the actual PYQs.
NDA2023
When yeast cells are O2 starved, fermentation serves as the source of energy. This results in the production of :
- A ATP + CO2 + Ethanol ✓
- B ATP + O2 + Pyruvate
- C ATP + CO2 + Lactic acid
- D ATP + O2 + Acetaldehyde
✓ Correct answer: (A)
Science & Technology › Biology & Health
CAPF2014
Consider the following statements describing the functions of plants
- Photosynthesis is a process to convert light energy from the Sun into chemical energy i.e., Carbohydrates are synthesized from carbon dioxide and water using sun light
- Fermentation or Zymology is a metabolic process that converts carbohydrate to alcohols and carbon dioxide
Which of the statements given above is/are correct ?
- A 1 only
- B 2 only
- C Both 1 and 2 ✓
- D Neither 1 nor 2
✓ Correct answer: (C)
Science & Technology › Biology & Health
CDS2014
What causes dough (a mixture of flour, water, etc.) to rise when yeast is added to it?
- A An increase in the temperature
- B An increase in the amount of the substance
- C An increase in the number of yeast cells
- D Release of carbon dioxide gas ✓
✓ Correct answer: (D)
Science & Technology › Biology & Health
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