How to Prepare for Science Subjects for UPSC Civil Services Prelims Exam

General science and technology is a subject that is equally important as other subjects for the UPSC civil services exam. Every year about 10-15 questions are asked from this section in the UPSC prelims of the IAS exams. So, you can assess the importance of this section. Generally, students from science or engineering backgrounds find this section easy, but others with a humanities background find this section a bit tough. It need not be if you follow some strategies. This article talks about how to go about preparing for the general science section of the UPSC civil services prelims.

This section can be classified into four:

  1. Biology
  2. Chemistry
  3. Physics
  4. Current affairs related to science and technology

General Science Syllabus for IAS Prelims:

Universe – Big Bang, Redshift, Blueshift

Star Formation – Stellar Evolution, Life Cycle of A Star

Solar System Formation – Nebular Theory of Laplace

Solar System – Planets, Inner Planets, Outer Planets

Sun – Internal Structure, Atmosphere

Nuclear Fission, Nuclear Reactor Types

India’s Three-Stage Nuclear Power Programme

Cell Organelles – Plant Cell vs. Animal Cell

Carbohydrates – Monosaccharides, Polysaccharides

Proteins – Amino Acids, Enzymes

Vitamins and Minerals – Deficiency Diseases

Fats – Healthy Fats and Unhealthy Fats

Animal Tissues – Epithelium, Connective Tissues

Human Digestive System – Digestive Glands

Respiratory System – NCERT General Science

Endocrine Glands and Hormones

Human Neural System – Human Brain

Muscular and Skeletal System

Nucleic acids – DNA and RNA, Recombinant DNA

Mitosis – Cell Cycle, Cell Division, Meiosis – Mitosis – Meiosis Comparison

Inheritance – Mendel’s Laws of Inheritance, Chromosomal Theory, Human Genome Project

Sex Determination – Genetic Disorders

Diseases Caused by Microorganisms

Microbes in Human Welfare – Useful Microbes

Immunity – Human Immune System

AIDS, Cancer – causes

Drugs and Alcohol Abuse

Diseases – Acute, Chronic, Communicable Diseases

Blood – Blood Groups – Formed Elements

Circulatory System, Double Circulation

Excretory System – Kidney, Urine Formation

Origin and Evolution of Life on Earth

Biological Classification

Five Kingdom Classifications of Plants and Animals

Plant Parts and Their Functions

Plant Kingdom – Thallophytes (Algae), Bryophytes, Pteridophytes

Plants with Seeds – Gymnosperms and Angiosperms

Plant Tissue – Meristematic – Simple, Complex Permanent Tissue

Plant Nutrition – Photosynthesis, Nitrogen Cycle, Fixation

Sexual and Asexual Reproduction in Plants

Classification of Animal Kingdom (Animalia)

Classification of Vertebrata (Phylum Chordata)

Human Reproductive System

Biotechnology – Genetic Engineering – Processes and Applications

Atomic Theory – Structure of an Atom

DELP (UJALA) Scheme – Comparison: LED – CFL – Incandescent Bulb

Sources of Study Material for Science Section in the UPSC Exam:

  • For core science subjects (chemistry, physics and biology), refer to the NCERT books from class VI to class X.
  • Refer to newspapers like The Hindu and its special science edition on Thursdays.
  • Refer to magazines like Science Reporter.
  • Other sources include the CSIR book series, books published by National Book Trust.

UPSC Civil Service Exam Preparation for Science Subjects

Areas to focus on


This is the most important of all core science subjects. Within biology, zoology takes precedence over botany in the UPSC civil service exam.

Focus area in botany – biological diversity, plant system, plant physiology

Focus area in zoology – animal classification, tissue structure, animal physiology.

Other focus areas – cell biology, genetics, biotechnology (transgenic crops), human health, microorganism, pathogens, communicable diseases and nutrition.

Let us take a look at a biology question asked in the 2013 UPSC prelims paper I:

  1. Q) Recombinant DNA technology (Genetic Engineering) allows genes to be transferred
  1. across different species of plants
  2. from animals to plants
  3. from microorganisms to higher organisms

Select the correct answer using the codes given below:

  • 1 only
  • 2 and 3 only
  • 1 and 3 only
  • 1,2 and 3

solution: a


Not many questions are asked from this subject except around 5 – 6 questions in the IAS prelims.

Focus areas – application based chemistry, food chemistry, fuels, and polymers, biometric systems, chemical changes in matter, radioactive elements, carbon dating, nuclear energy, neutrons, heavy water, nuclear reactors locations in India, elements and compounds that feature in the news, etc.

For instance, ethanol is commonly found in the news. Take a look at the following UPSC prelims question:

‘Ethanol’ has widespread usages and application. Consider the statements with reference to it

(1) It cannot be used as rocket propellant

(2) It can be used in thermometer

(3) It can be used as an antiseptic

(4) It causes cancer

(5) It can cause birth defects

(6) It cannot be used in DNA extraction because it is highly toxic

Correct code/s

(a) 1, 2, 3 and 5

(b) 1, 2, 4, 5 and 6

(c) 2, 3, 4 and 6

(d) 2, 3, 4 and 5

Answer: d

Technical details and chemical equations are not important.


Focus areas – light, sound, heat, electromagnetic radiation, electricity, magnetism, Newton’s Law, gravitation, Big Bang Theory, Higg’s Boson, dark energy, dark matter, graphene, forces in nature and naturally occurring phenomenon, rotation and revolution of the earth, a recent phenomenon in the news, etc.

Current Affairs in Science and Technology:

Like in every other subject, scout the newspapers and science magazines for the latest in scientific developments in India and abroad. As explained earlier, look for concepts involved in such events and developments.

Look out for Nobel Prize winners and their achievements.

Analysis of recent question papers reveals that a question in current affairs can be headed under science and technology as well as geography or geology. The following question which featured in the 2013 UPSC prelims question paper includes an understanding of concepts from both Physics and Geography.

  1. Q) Consider the following:
  1. Electromagnetic radiation
  2. Geothermal energy
  3. Gravitational force
  4. Plate movements
  5. Rotation of the earth
  6. Revolution of the earth

Which of the above are responsible for bringing dynamic changes on the surface of the earth?

(a) 1, 2, 3 and 4 only

(b) 1, 3, 5 and 6 only

(c) 2, 4, 5 and 6 only

(d) 1, 2, 3, 4, 5 and 6

Solution: d

Quick tips to remember while studying for general science in the IAS prelims exam:

  • Go through NCERT textbooks and revise them thoroughly.
  • Stick to the basics only. Preparing from the NCERTs is enough for the core subjects. No need to study scientific concepts in detail.
  • The idea is to cover the portions as much as possible; you don’t have to get a doctorate in science.
  • Update yourself on the latest scientific developments happening in India and abroad.
  • Know the Nobel Prize winners for the year and their area of work.
  • Follow ISRO, DRDO, Ministry of Science & Technology websites and news.
  • If any concept confuses you or you don’t understand it well enough from the NCERTs, look it up on the Internet.
  • Go through and practice previous year IAS question papers.
  • If there is an event in India related to science, always go through the basic science involved in that area.

For instance, consider the following question asked in the 2010 UPSC prelims:

India-based Neutrino Observatory is included by the Planning Commission as a mega-science project under the 11th five-Year Plan. In this context, consider the following statements:

  1. Neutrinos are chargeless elementary particles that travel close to the speed of light.
  2. Neutrinos are created in nuclear reactions of beta decay.
  3. Neutrinos have a negligible, but nonzero mass.
  4. Trillions of Neutrinos pass through human body every second.

Which of the statements given above are correct?

(a) 1 and 3 only

(b) 1, 2 and 3 only

(c) 2, 3 and 4

(d) 1, 2, 3 and 4

Solution: d

  • Focus on naturally occurring phenomenon and how they occur. For example, consider the following question asked in 2013 IAS prelims:

During a thunderstorm, the thunder in the skies is produced by the

  1. Meeting of cumulonimbus clouds in the sky
  2. Lightning that separates the nimbus clouds
  3. Violent upward movement of air and water particles

Select the correct answer using the codes given below.

(a) 1 only

(b) 2 and 3

(C) 1 and 3

(d) None of the above produces the thunder

Solution: C

Related Links

UPSC 2021 Calendar UPSC Books
UPSC 2021 UPSC Notes


  1. Plz guide me if I don’t have time to go through ncerts n make notes. Then can i rely on arihant encyclopedia science book

    1. For the Science subject, you can also rely on current affairs.

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