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CCEA GCSE Biology: complete guide to the two units, the practical skills and the exams

A complete guide to CCEA GCSE Biology (code 6568). Covers Unit 1 (Cells, Living Processes and Biodiversity), Unit 2 (Body Systems, Genetics, Microorganisms and Health) and Unit 3 Practical Skills, the Foundation and Higher tiers, how the written exams are structured and marked, and how to study each topic for top grades.

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CCEA GCSE Biology (specification code 6568) is a single GCSE set and marked by CCEA in Northern Ireland. It is made of two written units and a practical-skills unit, sat at either Foundation or Higher tier. This page is the index: below is a map of the six study modules, the exam structure, the tiers, and how to study each one.

The CCEA Biology units and study modules

CCEA organises the content into Unit 1 and Unit 2, each split into numbered content sections, plus Unit 3 Practical Skills. We have grouped the specification into six study modules that follow the CCEA sections closely, and each module has an overview guide and a focused answer page for every examinable topic.

Cells and life processes
The chemistry and cell biology that everything builds on: cells and microscopy, photosynthesis, leaf structure and gas exchange, nutrition and food tests, enzymes, and the digestive system (Unit 1 sections 1.1 to 1.4). Start with the Cells and life processes overview.
Transport, respiration and coordination
How substances move and how the body is controlled: breathing and the respiratory system, the nervous system and the eye, hormones and homeostasis, osmosis and plant transport, and the circulatory system, blood and the heart (Unit 1 sections 1.5 to 1.6 and Unit 2 sections 2.1 to 2.2). Start with the Transport, respiration and coordination overview.
Ecology and the environment
Organisms and their surroundings: ecological relationships, energy flow and food chains, the carbon and nitrogen cycles, sampling and biodiversity, and human impact on the environment (Unit 1 sections 1.7 to 1.8). Start with the Ecology and the environment overview.
Genetics and cell division
How information is stored and passed on: chromosomes, genes and DNA, protein synthesis, mitosis and meiosis, monohybrid inheritance, and sex determination and genetic disorders (Unit 2 sections 2.3 to 2.4). Start with the Genetics and cell division overview.
Variation, reproduction and applied genetics
Where differences come from and how we use genetics: variation, natural selection and evolution, the reproductive system and hormones, selective breeding, and genetic engineering and cloning (Unit 2 sections 2.5 to 2.7). Start with the Variation, reproduction and applied genetics overview.
Microorganisms and health
Microbes, disease and treatment: microorganisms and biotechnology, defence against disease, vaccination and the immune system, and medicines, antibiotics and drugs (Unit 2 sections 2.8 to 2.10). Start with the Microorganisms and health overview.

Exam structure

CCEA GCSE Biology is assessed by two written units and one practical-skills unit, all sat at the same tier.

  • Unit 1 Cells, Living Processes and Biodiversity is worth 35%. Foundation is 1 hour 15 minutes and Higher is 1 hour 30 minutes.
  • Unit 2 Body Systems, Genetics, Microorganisms and Health is worth 40%. Foundation is 1 hour 30 minutes and Higher is 1 hour 45 minutes.
  • Unit 3 Practical Skills is worth 25% and is internally assessed, using prescribed practicals and a practical task rather than a written exam.

The written papers use structured short-answer questions, data and calculation questions and longer questions, with marks for the quality of written communication on extended answers. A calculator is allowed.

Foundation and Higher tier

The course is tiered. Foundation tier targets grades C to G and Higher tier targets grades A star to D, with an allowed E. Higher-tier-only content (printed in bold italics in the specification) includes the symbol equation for photosynthesis, more detail on the nitrogen cycle, the lock and key model, harder genetic reasoning and tougher calculations. You sit both written units at the same tier.

How to study each module

Work statement by statement against the CCEA specification, because questions are written directly from it. For each topic: learn the definitions precisely, link structure to function, rehearse every process as an ordered sequence, and drill the maths (magnification, percentage change, rates, ratios and energy transfer) until it is automatic. Then use CCEA past papers to practise the exact question styles and command words, and prepare the prescribed practicals for Unit 3.

Pick a module overview above to begin, then work through each topic answer page and finish with the matching quiz.

Biology guides

In-depth written guides with paired practice quizzes.

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Biology practice quizzes

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Common questions about Biology

How is CCEA GCSE Biology structured?
CCEA GCSE Biology (code 6568) is a single GCSE made of three units. Unit 1 Cells, Living Processes and Biodiversity is a written exam worth 35 percent. Unit 2 Body Systems, Genetics, Microorganisms and Health is a written exam worth 40 percent. Unit 3 Practical Skills is internally assessed and worth 25 percent. It is tiered, so you sit either Foundation or Higher papers.
What are the CCEA GCSE Biology exam papers?
There are two written papers. Unit 1 at Foundation is 1 hour 15 minutes and at Higher is 1 hour 30 minutes, worth 35 percent. Unit 2 at Foundation is 1 hour 30 minutes and at Higher is 1 hour 45 minutes, worth 40 percent. Both use structured short-answer questions, data and calculation questions, and longer questions including quality of written communication marks. Unit 3 assesses practical skills rather than being a written paper.
What topics are in CCEA GCSE Biology?
Unit 1 covers cells and microscopy, photosynthesis and plants, nutrition and food tests, enzymes and digestion, breathing and the respiratory system, the nervous system and hormones, and ecological relationships, energy flow and human impact. Unit 2 covers osmosis and plant transport, the circulatory system, chromosomes, genes, DNA and protein synthesis, cell division and genetics, variation and natural selection, reproduction, applied genetics, microorganisms and biotechnology, defence against disease and medicines and drugs.
What is the difference between Foundation and Higher tier?
CCEA GCSE Biology is tiered. Foundation tier targets grades C to G and Higher tier targets grades A star to D, with an allowed E. Higher tier papers are longer and include the more demanding content, such as the symbol equation for photosynthesis, more detail on the nitrogen cycle, the lock and key model, dihybrid reasoning and harder calculations. You sit both units at the same tier, and the tier sets the grades available.
How much practical and maths work is in CCEA GCSE Biology?
Practical skills are assessed in Unit 3, which is worth 25 percent and uses prescribed practicals, a booklet and a practical task rather than a written exam. Maths runs through both written units: magnification and scale calculations, percentage change in osmosis, rates from graphs, ratios and probabilities in genetics, energy transfer between trophic levels, and reading data and graphs. A calculator is allowed in the written papers.
How should I revise CCEA GCSE Biology?
Work topic by topic against the specification statements, because CCEA writes questions straight from them. Learn definitions precisely, link structure to function in every system, rehearse each process such as the reflex arc, the cardiac cycle and protein synthesis as an ordered sequence, and drill the calculations until they are automatic. Practise CCEA past papers to learn the command words such as Describe, Explain, Calculate, Suggest and Evaluate, and prepare the prescribed practicals for Unit 3.
What's the difference between mitosis and meiosis?
Mitosis produces two identical diploid cells (for growth and repair). Meiosis produces four genetically distinct haploid cells (for sexual reproduction).
How does protein synthesis work?
Transcription (DNA → mRNA in the nucleus) then translation (mRNA → polypeptide at the ribosome). tRNA brings amino acids that the ribosome links into the protein sequence the mRNA codes for.
What's homeostasis?
The maintenance of a stable internal environment (temperature, blood glucose, pH) despite external change — usually via negative feedback loops involving receptors, control centres, and effectors.
How does evolution by natural selection work?
Variation exists in a population → some variants survive and reproduce better in a given environment → those traits become more common over generations. Requires heritable variation, differential reproductive success, and time.
What's the difference between an antibody and an antigen?
Antigen: a molecule (often on a pathogen) that triggers an immune response. Antibody: a Y-shaped protein the immune system makes to bind specifically to that antigen.