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Topic Base pairing
Asked 2 times across 2 UPSC exams over 40 years (1985–2025), peaking in 1985.
Key insights
- Most tested in CSE — 1 of 2 PYQs
- Most asked in 1985
- Recurs across 2 years (1985–2025)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
CSE 1985 → NDA 2025
How the concept evolved
Long-running — most appearances (1 of 2) 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.
NDA2025
Which is the correct base pairing found in a normal DNA molecule?
- A Adenine pairs with Thymine ✓
- B Adenine pairs with Guanine
- C Adenine pairs with Cytosine
- D Thymine pairs with Guanine
✓ Correct answer: (A)
Science & Technology › Biology & Health
CSE1985
Genetic code is made up by the four-letter alphabet forming the pairs
- A AC, CA, T G, GT
- B AG, GA, CA, TC
- C T G, GT, AC, CA
- D AT, TA, CG, G C ✓
✓ Correct answer: (D)
Science & Technology › Biotech & Genetics
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