This was asked in 2025 GS paper
I keep saying you must have basic knowledge of subjects before you jump into advance knowledge.
For science you may read from 7th to 10th science and selective chapters from 11th and 12th ncerts( Pyq based) again extra focus on few chapters Based on pyqs analysis.

Question from 2025 PRELIMS

One of the favourite topics of UPSC
Virus and other microorganisms like Bacteria and Fungi.
You must read about these microorganisms without failure.

Let us understand and excel UPSC prelims through pyqs.

VIRUSES (Very important for Prelims)
Basic facts
• Acellular (not made of cells)
• Obligate intracellular parasites → reproduce only inside host cells
• Can infect plants, animals, bacteria (bacteriophages)
Structure
• Genetic material: Either DNA or RNA (never both)
• Protein coat called capsid
• Some have envelope (lipid layer) → derived from host cell membrane
Key points
• No metabolism of their own
• Do not respond to antibiotics
• Can be crystallised (living + non-living nature)
• Cause diseases: COVID-19, AIDS, Influenza, Dengue, Rabies

BACTERIA
Basic facts
• Prokaryotic, unicellular organisms
• Cell wall made of peptidoglycan (murein)
• Size: 0.5–5 μm
Structure
• No true nucleus (nucleoid)
• Ribosomes: 70S
• May have flagella, pili, capsule
Shapes (asked frequently)
• Cocci – spherical
• Bacilli – rod-shaped
• Spirilla – spiral
• Vibrios – comma-shaped
Reproduction
• Mainly by binary fission
• Genetic variation by conjugation, transformation, transduction
Importance
Useful:
• Nitrogen fixation (Rhizobium)
• Curd formation (Lactobacillus)
• Antibiotics (Streptomyces)
Harmful:
• Tuberculosis, Cholera, Typhoid, Plague

FUNGI
Basic facts
• Eukaryotic, heterotrophic
• Cell wall made of chitin
• Mostly multicellular (except yeast)
Structure
• Body made of hyphae
• Network of hyphae = mycelium
Nutrition
• Saprophytic (dead matter)
• Parasitic
• Symbiotic:
• Lichens = algae + fungi
• Mycorrhiza = fungi + plant roots
Reproduction
• Asexual: spores, budding
• Sexual: plasmogamy → karyogamy → meiosis
Importance
Useful:
• Antibiotics (Penicillium → Penicillin)
• Fermentation (Yeast)
• Decomposition
Harmful:
• Plant diseases (rust, smut)
• Human diseases (ringworm, athlete’s foot)

Whether we realise or not Microorganisms are playing a crucial role in our day to day life that’s why Upsc expects every aspirant and officer to know about them.

Upsc is not asking themes randomly but every question or theme they are picking up are based on their influence on people and nation.

So if you understand this aspect then you will read right and good content.

खाकी और खद्दर में, भैया, गजब connection होता है
बड़ा कांड हो जाने पर ही यहाँ attention हौता ह
Load लेते हैं क्यूँ बेकार में
आइए ना हमरा Bihar में
आइए ना हमरा Bihar में
(...हमरा Bihar में)

Between khaki and khaddar, brother, there is an amazing connection here.
Only when a big scandal happens does anyone pay attention.
Why take unnecessary stress?
Come to our Bihar.
Come to our Bihar.
(…to our Bihar)

Not just Bihar but applies to all states..

Wonderful and enlightening lyrics…

we all know this but we still remain mute spectators…

If you remember, last year before Prelims we started an initiative where aspirants who had prepared subject-wise themes/topics based on PYQs shared their work with me. I then shared it on the channel with due credits to the contributors.

We will continue the same initiative this year as well. It can be extremely helpful for many students who struggle to identify recurring themes or end up missing important areas.

Those who have analysed GS and CSAT papers up to 2025 and prepared a theme/topic list may kindly DM me.
@rajinikanthramareddipeta

Last time also I said India is moving beyond the traditional countries like USA China Russia Japan Etc in the Bilateral ties and also to overcome de globalisation effect. India Germany pact is one of the emerging relations which will help to improve India’s trade basket and also overall economic social and cultural relations.

Upsc aspirants should learn these aspects to write matured answers in International relations questions even if they ask indirectly.

Not just this,
we also witness many unethical advertising practices in the coaching industry, especially in the online space. Offers such as “₹99 CSAT course” or “₹499 GS course” are often nothing more than marketing gimmicks aimed at attracting students rather than delivering genuine value.

At the very least, educated students should exercise critical judgment and avoid falling for such stunts.

Useful for Mains Answers substantiation.

Very important PDF for Prelims 2026.
Stop reading random Science and Technology topics. Focus only on these PYQ-based keywords, build strong conceptual clarity, and then connect them with the latest current affairs related to these themes.

Let us read smart, avoid information overload, and reduce unnecessary stress.