KS3 Science – 20 Key Questions | Master Revision Quiz

🌿 Biology Topics

Cells are the basic unit of life; animal, plant, and bacterial cells have different structures

Photosynthesis: CO₂ + H₂O → glucose + O₂ (requires light energy and chlorophyll)

Respiration releases energy from glucose; aerobic uses O₂, anaerobic does not

DNA carries genetic information; reproduction can be sexual or asexual

Ecosystems involve food chains, food webs, and energy transfer between organisms

The human body systems: circulatory, digestive, respiratory, nervous, skeletal

⭐ Must-Remember

Photosynthesis equation: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
Aerobic respiration: glucose + oxygen → CO₂ + water + energy
Cell organelles: nucleus (control), mitochondria (energy), ribosomes (protein synthesis), cell membrane (controls entry/exit)

⚗️ Chemistry Topics

All matter is made of atoms; elements are pure substances of one atom type

The Periodic Table organises elements by atomic number; groups share similar properties

Chemical reactions rearrange atoms; conservation of mass always applies

Acids and alkalis: pH scale 0–14; pH 7 = neutral, below 7 = acid, above 7 = alkali

Mixtures can be separated by filtration, distillation, crystallisation, or chromatography

Metals react with acids to form a salt + hydrogen gas

⭐ Must-Remember

Reactivity series (most → least): K, Na, Ca, Mg, Al, Zn, Fe, Sn, Pb, Cu, Ag, Au
Indicators: litmus (red in acid, blue in alkali), universal indicator (full pH scale)
Word equation for neutralisation: acid + alkali → salt + water

⚡ Physics Topics

Forces: measured in Newtons (N); balanced forces = no change in motion

Speed = distance ÷ time (m/s); acceleration = change in velocity ÷ time (m/s²)

Energy cannot be created or destroyed; it is transferred between stores

Waves: transverse (light) or longitudinal (sound); all properties follow wave equation: wave speed = frequency × wavelength

Electricity: current (A), voltage (V), resistance (Ω); Ohm's Law: V = I × R

The electromagnetic spectrum: radio, microwave, infrared, visible, UV, X-ray, gamma

⭐ Must-Remember

Speed formula: v = d / t | Ohm's Law: V = I × R
Wave equation: v = f × λ | Weight: W = m × g (g = 10 N/kg on Earth)
Energy conservation: total energy in = total energy out (some wasted as heat)

KS3 Science
Master Quiz

📚 KS3 Science – Key Concepts Overview