1
Cell Structure and Organisation
Identify cell structures in light and electron images, compare plant and animal cells, and explain specialised-cell adaptations.
Biology notes for O-Level and SEC G3
Choose a chapter or download the full set. These notes follow the 2027 K325 syllabus.
Last updated: 2026-10-04
- K325
- 2027 SEC G3 syllabus
- 14
- topics
- 6093
- O-Level reference code
Choose the syllabus for your exam year
Sitting the exam in 2027? Use K325. Sitting in 2026? Keep using the current 6093 syllabus and your school materials.
K325 is the controlling source for the 2027 Pure Biology track. The existing Sec 3 Biology guide remains available for foundation revision; this hub does not replace it.
Pure or Combined? Pure Biology K325 has 14 top-level topics. Combined Biology has 12, omits standalone Excretion and Homeostasis topics, and narrows Reproduction.
All topics
01
Cells and The Chemistry of Life
2
Movement of Substances
Distinguish diffusion, osmosis, and active transport using gradients, membranes, energy, and context.
3
Biological Molecules
Connect carbohydrates, proteins, fats, enzymes, food tests, and molecular function to experimental evidence.
02
The Human Body: Maintaining Life
4
Nutrition in Humans
Trace alimentary-canal functions, digestion, absorption, liver roles, and alcohol effects within the K325 boundary.
5
Transport in Humans
Connect blood components, vessels, the heart, circulation, tissue exchange, and disease risk.
6
Respiration in Humans
Separate breathing, gas exchange, and respiration, then relate structures and rates to energy demand.
7
Excretion in Humans
Define excretion and trace urinary structures, nephron processes, urine production, and dialysis.
8
Homeostasis, Co-ordination and Response in Humans
Use stimulus-response and feedback pathways to explain nervous, hormonal, and internal regulation.
9
Infectious Diseases in Humans
Compare bacteria and viruses, then connect influenza, pneumococcus, vaccination, antibiotics, and resistance.
03
Living Together: Plants, Animals and Ecosystems
10
Nutrition and Transport in Flowering Plants
Link photosynthesis, leaf and root adaptations, xylem, phloem, transpiration, and limiting factors.
11
Organisms and their Environment
Interpret energy flow, carbon cycling, global warming, pollution, conservation, and sustainable resource use.
04
Continuity of Life
12
Molecular Genetics
Connect DNA, genes, chromosomes, the polypeptide code, transgenic insulin production, and ethical evaluation.
13
Reproduction
Compare sexual and asexual reproduction and explain human and plant reproductive processes within scope.
14
Inheritance
Use genetic notation, simple crosses, ABO codominance, sex chromosomes, mutation, variation, and selection.
Need a different route?
- IP students should use the IP upper-secondary Biology notes and follow your current school scope first.
- The existing Sec 3 Biology foundation guide remains available for Sec 3 foundation revision.
- For laboratory skills and practical-paper preparation, use the O-Level Biology practical hub.
Source and scope
Official curriculum source: SEAB 2027 SEC G3 Biology K325 syllabus. Checked 15 July 2026. Recheck codes, outcomes and assessment details before annual updates.
The focus lines are Eclat revision guidance. They are not quoted syllabus text and do not replace the official learning outcomes.
Common questions
Is this the 2027 Biology syllabus?
This page lists the main topics in the official 2027 SEC G3 Biology K325 syllabus. Use the linked SEAB syllabus to check exactly what can be assessed and how the papers are organised.
Why does the page also say O-Level and 6093?
O-Level is still familiar reader language and 6093 is the 2026-and-earlier reference code. Students sitting in 2027 should use K325, while 2026 candidates must follow their current legacy syllabus and school instructions.
Can IP students use this page?
IP students can compare topics here, but should use the separate IP notes page for revision. IP schools set their own topic order, depth, and assessment requirements. Follow current school materials first.