General Science Revision: Vitamins, Units and the Human Body

General science in competitive exams is usually straightforward school-level content. These are the facts that come up most.

Vitamins and deficiency diseases

Vitamin	Deficiency disease	Source
A	night blindness	carrots, milk, green vegetables
B1 (thiamine)	beriberi	whole grains
C	scurvy	citrus fruits
D	rickets	sunlight, fish
K	poor blood clotting	leafy vegetables

The human body

• An adult has 206 bones.
• The heart has four chambers.
• Blood groups: A, B, AB and O.
• The largest organ is the skin.
• The smallest bone is in the ear.
• The liver is the largest internal organ.
• Normal body temperature is about 37 °C.

Physics

Concept	Fact
Speed of light	about 3 × 10⁸ metres per second
Newton's laws	first: inertia; second: F = ma; third: action and reaction
SI unit of force	newton (N)
SI unit of energy	joule (J)
SI unit of power	watt (W)
SI unit of frequency	hertz (Hz)
Sound	needs a medium and cannot travel in a vacuum

Chemistry

• pH below 7 is acidic, 7 is neutral and above 7 is basic.
• Water is H₂O; common salt is NaCl.
• Atomic number is the number of protons.
• Noble gases (helium, neon, argon) are largely unreactive.

Biology

• Photosynthesis: plants make food from carbon dioxide, water and sunlight, releasing oxygen.
• Chlorophyll gives leaves their green colour.
• Cell is the basic unit of life.
• DNA carries genetic information.

Environment

• Ozone layer absorbs harmful ultraviolet radiation.
• Greenhouse gases include carbon dioxide and methane.

Space

• The Sun is a star.
• Jupiter is the largest planet, and Mercury the smallest.
• ISRO is India's space agency.

Tips

1. Use tables and revise them.
2. Link facts to daily life.
3. Practise MCQs to check recall.

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