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Biology Revision

Cells, body systems & ecosystems — part of Science on KODO.

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Biology is a core area of KS3 Science in the national curriculum. It covers essential concepts that build the foundation for GCSE study and beyond.

This topic includes subtopics such as Cells and microscopes, Human body systems (circulatory, digestive, respiratory), Plants and photosynthesis, Ecosystems and food chains and more. Each area is tested with multiple-choice questions that include detailed explanations to deepen your understanding.

Quick Reference

Plant cell extrasCell wall, chloroplasts, large vacuole
Photosynthesis equation6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
Aerobic respirationGlucose + O₂ → CO₂ + H₂O + energy
DNA locationNucleus of the cell

Key Definitions

Cell
The basic building block of all living organisms.
Photosynthesis
The process plants use to convert light energy into glucose: CO₂ + H₂O → C₆H₁₂O₆ + O₂
Respiration
The process cells use to release energy from glucose: C₆H₁₂O₆ + O₂ → CO₂ + H₂O + energy
Diffusion
The net movement of particles from an area of high concentration to low concentration.
Ecosystem
A community of living organisms interacting with their physical environment.

What You'll Cover

Cells and microscopes
Human body systems (circulatory, digestive, respiratory)
Plants and photosynthesis
Ecosystems and food chains
Reproduction and variation
Cells and cell structures
Body systems (digestion, circulation, respiration)
Photosynthesis
Genetics and inheritance

Test Yourself — Biology

Try 3 quick questions. No account needed.

Quick Quiz

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Memory Tricks & Mnemonics

"MRS GREN" — Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition

The 7 characteristics of living things.

"Richard Of York Gave Battle In Vain" — but for Biology: cells → tissues → organs → organ systems → organisms

The levels of organisation in living things.

Frequently Asked Questions

What is Cell in Science?+
The basic building block of all living organisms.
What is Photosynthesis in Science?+
The process plants use to convert light energy into glucose: CO₂ + H₂O → C₆H₁₂O₆ + O₂
What is Respiration in Science?+
The process cells use to release energy from glucose: C₆H₁₂O₆ + O₂ → CO₂ + H₂O + energy
What is Diffusion in Science?+
The net movement of particles from an area of high concentration to low concentration.
What does Biology cover in KS3 Science?+
Biology in KS3 Science covers Cells and microscopes, Human body systems (circulatory, digestive, respiratory), Plants and photosynthesis, Ecosystems and food chains, Reproduction and variation, Cells and cell structures, Body systems (digestion, circulation, respiration), Photosynthesis. Cells, body systems & ecosystems.
What is the best way to revise Biology?+
Test yourself rather than re-reading notes. Do a short Biology quiz, read the explanation for every answer you get wrong, then come back to those questions a few days later. KODO does this automatically with spaced repetition, and you can turn any topic into printable flash cards.
Is Biology revision on KODO free?+
Yes. KODO is free for everyone until Friday 18 December 2026, with unlimited quizzes on Biology and every other topic. After that there is still a free plan with daily quizzes.

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