Edexcel, specification XBI11
Edexcel International AS Level Biology
Edexcel International AS Level Biology (XBI11) is sat as three unit exams: Unit 1 and Unit 2 (1 hour 30 minutes, 80 marks each) and Unit 3 on practical skills (1 hour 20 minutes, 50 marks). Here are all 4 topics, with free revision notes, exam questions with mark schemes, flashcards and mind maps.
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Units 1 and 2 each test two topics; Unit 3 tests practical skills · Unit 1: 1 hour 30 minutes · Unit 2: 1 hour 30 minutes · Unit 3: 1 hour 20 minutes- 1Molecules, Transport and HealthWater, carbohydrates and lipids · The heart, blood vessels and haemoglobin · Cardiovascular disease and its causes · Health risks, evidence and treatment4 subtopics
- 2Membranes, Proteins, DNA and Gene ExpressionGas exchange, membranes and transport · Proteins and enzymes · DNA, the genetic code and gene expression · Inheritance, cystic fibrosis and genetic screening4 subtopics
- 3Cell Structure, Reproduction and DevelopmentCells, tissues and organelles · Microscopy and measuring cells · Chromosomes, meiosis and gametes · Mitosis and the cell cycle · Stem cells, gene expression and phenotype5 subtopics
- 4Plant Structure and Function, Biodiversity and ConservationPlant cells and cell walls · Plant tissues, fibres and mineral nutrition · Bacterial growth, plant medicines and drug testing · Classification and biodiversity · Niche, allele frequency and conservation5 subtopics
About Edexcel International AS Level Biology
Pearson Edexcel International Advanced Subsidiary Biology (XBI11) is the first half of the International A Level: Units 1 to 3, covering topics 1 to 4, graded A to E. It can be a qualification on its own or count for 50% of the International A Level. Units 1 and 2 each examine two topics, and Unit 3 is a written paper on practical skills based on core practicals 1 to 9. Each unit can be sat in January, June or October. This course leaves out the content labelled A Level only.
Unit 1: Molecules, Diet, Transport and Health
- Time
- 1 hour 30 minutes
- Marks
- 80 marks, 40% of the IAS
- Topics
- Topic 1 Molecules, Transport and Health and Topic 2 Membranes, Proteins, DNA and Gene Expression
Unit 2: Cells, Development, Biodiversity and Conservation
- Time
- 1 hour 30 minutes
- Marks
- 80 marks, 40% of the IAS
- Topics
- Topic 3 Cell Structure, Reproduction and Development and Topic 4 Plant Structure and Function, Biodiversity and Conservation
Unit 3: Practical Skills in Biology I
- Time
- 1 hour 20 minutes
- Marks
- 50 marks, 20% of the IAS
- Topics
- A written paper on practical skills from Units 1 and 2 (core practicals 1 to 9): planning, measurements and processing results
Edexcel International AS Level Biology exams
- Level
- Untiered: everyone sits Units 1, 2 and 3, graded A to E
- Sittings
- January, June and October, unit by unit. Any unit can be resat
- January 2027
- Pearson publishes a timetable for each series. Your school enters you unit by unit, so check your dates and start times with your exams officer.
- Grade boundaries
- Pearson Edexcel grade boundaries (see the International Advanced Level files). They change every series.
Edexcel IAL Biology guide: units and exam series · Edexcel International AS Level Biology past papers