Cambridge International AS & A Level Biology 9700 PDF Syllabus (2025, 2026, 2027)

Syllabus Cambridge International AS & A Level Biology 9700 Use this syllabus for exams in 2025, 2026 and 2027. Exams are available in the June and November series. Also available for examination in March 2025, 2026 and 2027 for India. Version 1 For the purposes of...

Syllabus Cambridge International AS & A Level Biology 9700 Use this syllabus for exams in 2025, 2026 and 2027. Exams are available in the June and November series. Also available for examination in March 2025, 2026 and 2027 for India. Version 1 For the purposes of screen readers, any mention in this document of Cambridge IGCSE refers to Cambridge International General Certificate of Secondary Education. Why choose Cambridge International? Cambridge International prepares school students for life, helping them develop an informed curiosity and a lasting passion for learning. We are part of Cambridge University Press & Assessment, which is a department of the University of Cambridge. Our Cambridge Pathway gives students a clear path for educational success from age 5 to 19. Schools can shape the curriculum around how they want students to learn – with a wide range of subjects and flexible ways to offer them. It helps students discover new abilities and a wider world, and gives them the skills they need for life, so they can achieve at school, university and work. Our programmes and qualifications set the global standard for international education. They are created by subject experts, rooted in academic rigour and reflect the latest educational research. They provide a strong platform for students to progress from one stage to the next, and are well supported by teaching and learning resources. We review all our syllabuses regularly, so they reflect the latest research evidence and professional teaching practice – and take account of the different national contexts in which they are taught. We consult with teachers to help us design each syllabus around the needs of their learners. Consulting with leading universities has helped us make sure our syllabuses encourage students to master the key concepts in the subject and develop the skills necessary for success in higher education. Our mission is to provide educational benefit through provision of international programmes and qualifications for school education and to be the world leader in this field. Together with schools, we develop Cambridge learners who are confident, responsible, reflective, innovative and engaged – equipped for success in the modern world. Every year, nearly a million Cambridge students from 10 000 schools in 160 countries prepare for their future with the Cambridge Pathway. School feedback: ‘We think the Cambridge curriculum is superb preparation for university.’ Feedback from: Christoph Guttentag, Dean of Undergraduate Admissions, Duke University, USA Quality management Cambridge International is committed to providing exceptional quality. In line with this commitment, our quality management system for the provision of international qualifications and education programmes for students aged 5 to 19 is independently certified as meeting the internationally recognised standard, ISO 9001:2015. Learn more at www.cambridgeinternational.org/ISO9001 © Cambridge University Press & Assessment September 2022 Cambridge Assessment International Education is part of Cambridge University Press & Assessment. Cambridge University Press & Assessment is a department of the University of Cambridge. Cambridge University Press & Assessment retains the copyright on all its publications. Registered centres are permitted to copy material from this booklet for their own internal use. However, we cannot give permission to centres to photocopy any material that is acknowledged to a third party even for internal use within a centre. Contents Why choose Cambridge International?......................................................................... 2 1 Why choose this syllabus?......................................................................................... 4 2 Syllabus overview........................................................................................................ 8 Aims 8 Content overview 9 Assessment overview 10 Assessment objectives 12 3 Subject content..........................................................................................................14 AS Level subject content 15 A Level subject content 32 4 Details of the assessment........................................................................................ 49 Paper 1 Multiple Choice 49 Paper 2 AS Level Structured Questions 49 Paper 3 Advanced Practical Skills 49 Paper 4 A Level Structured Questions 49 Paper 5 Planning, Analysis and Evaluation 49 Command words 50 5 Practical assessment.................................................................................................51 Introduction 51 Paper 3 Advanced Practical Skills 51 Paper 5 59 6 Additional information............................................................................................... 63 Mathematical requirements 63 Mathematical formulae (A Level only) 65 Notes on the use of statistics in Biology (A Level only) 67 7 What else you need to know.................................................................................... 68 Before you start 68 Making entries 69 Accessibility and equality 69 After the exam 70 How students, teachers and higher education can use the grades 71 Grade descriptions 71 Changes to this syllabus for 2025, 2026 and 2027 72 Important: Changes to this syllabus For information about changes to this syllabus for 2025, 2026 and 2027, go to page 72. The latest syllabus is version 1, published September 2022. There are no significant changes which affect teaching.  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027 1 Why choose this syllabus? Key benefits The best motivation for a student is a real passion for the subject they’re learning. By offering students a variety of Cambridge International AS & A Levels, you can give them the greatest chance of finding the path of education they most want to follow. With over 50 subjects to choose from, students can select the ones they love and that they’re best at, which helps motivate them throughout their studies. Cambridge learner Following a Cambridge International AS & A Level programme helps students develop abilities which universities value highly, including: a deep understanding of their subjects higher order thinking skills – analysis, critical thinking, problem solving presenting ordered and coherent arguments independent learning and research. Cambridge International AS & A Level Biology develops a set of transferable skills including handling data, practical problem-solving, and applying the scientific method. Learners develop relevant attitudes, such as concern for accuracy and precision, objectivity, integrity, enquiry, initiative and inventiveness. They acquire the essential scientific skills required for progression to further studies or employment. Our approach in Cambridge International AS & A Level Biology encourages learners to be: confident, secure in their knowledge, keen to explore further and able to communicate effectively through the language of science responsible, developing efficient and safe scientific practices and working collaboratively with others reflective, able to evaluate evidence to draw informed and appropriate conclusions and recognising that the applications of science have the potential to affect the individual, the community and the environment innovative, applying problem-solving skills to novel situations and engaging with new tools and techniques, including information technology, to develop successful approaches engaged, developing an enquiring mind, keen to apply scientific skills in everyday life. School feedback: ‘Cambridge students develop a deep understanding of subjects and independent thinking skills.’ Feedback from: Principal, Rockledge High School, USA Back to contents page www.cambridgeinternational.org/alevel 4  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Why choose this syllabus? Key concepts Key concepts are essential ideas that help students develop a deep understanding of their subject and make links between different aspects. Key concepts may open up new ways of thinking about, understanding or interpreting the important things to be learned. Good teaching and learning will incorporate and reinforce a subject’s key concepts to help students gain: a greater depth as well as breadth of subject knowledge confidence, especially in applying knowledge and skills in new situations the vocabulary to discuss their subject conceptually and show how different aspects link together a level of mastery of their subject to help them enter higher education. The key concepts identified below, carefully introduced and developed, will help to underpin the course you will teach. You may identify additional key concepts which will also enrich teaching and learning. The key concepts for Cambridge International AS & A Level Biology are: Cells as the units of life A cell is the basic unit of life and all organisms are composed of one or more cells. There are two fundamental types of cell: prokaryotic and eukaryotic. Understanding how cells work provides an insight into the fundamental processes of all living organisms. Biochemical processes Cells are dynamic structures within which the chemistry of life takes place. Biochemistry and molecular biology help to explain how and why cells function as they do. DNA, the molecule of heredity Cells contain the molecule of heredity, DNA. DNA is essential for the continuity and evolution of life by allowing genetic information to be stored accurately, to be copied to daughter cells, to be passed from one generation to the next and for the controlled production of proteins. Rare errors in the accurate copying of DNA known as mutations result in genetic variation and are essential for evolution. Natural selection Natural selection acts on genetic variation and is the major mechanism in evolution, including speciation. Natural selection results in the accumulation of beneficial genetic mutations within populations and explains how populations can adapt to meet the demands of changing environments. Organisms in their environment All organisms interact with their biotic and abiotic environment. Studying these interactions allows biologists to understand better the effect of human activities on ecosystems, to develop more effective strategies to conserve biodiversity and to predict more accurately the future implications for humans of changes in the natural world. Observation and experiment The different fields of biology are intertwined and cannot be studied in isolation. Observation, enquiry, experimentation and fieldwork are fundamental to biology, allowing relevant evidence to be collected and considered as a basis on which to build new models and theories. Such models and theories are further tested by experimentation and observation in a cyclical process of feedback and refinement, allowing the development of robust and evidence-based conceptual understandings. Back to contents page www.cambridgeinternational.org/alevel 5  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Why choose this syllabus? International recognition and acceptance Our expertise in curriculum, teaching and learning, and assessment is the basis for the recognition of our programmes and qualifications around the world. Every year thousands of students with Cambridge International AS & A Levels gain places at leading universities worldwide. Our programmes and qualifications are valued by top universities around the world including those in the UK, US (including Ivy League universities), Europe, Australia, Canada and New Zealand. UK NARIC*, the national agency in the UK for the recognition and comparison of international qualifications and skills, has carried out an independent benchmarking study of Cambridge International AS & A Level and found it to be comparable to the standard of AS & A Level in the UK. This means students can be confident that their Cambridge International AS & A Level qualifications are accepted as equivalent, grade for grade, to UK AS & A Levels by leading universities worldwide. Cambridge International AS Level Biology makes up the first half of the Cambridge International A Level course in biology and provides a foundation for the study of biology at Cambridge International A Level. Depending on local university entrance requirements, students may be able to use it to progress directly to university courses in biology or some other subjects. It is also suitable as part of a course of general education. Cambridge International A Level Biology provides a foundation for the study of biology or related courses in higher education. Equally it is suitable as part of a course of general education. For more information about the relationship between the Cambridge International AS Level and Cambridge International A Level see the ‘Assessment overview’ section of the Syllabus overview. We recommend learners check the Cambridge recognition database and university websites to find the most up-to-date entry requirements for courses they wish to study. * Due to the United Kingdom leaving the European Union, the UK NARIC national recognition agency function was re-titled as UK ENIC on 1 March 2021, operated and managed by Ecctis Limited. From 1 March 2021, international benchmarking findings are published under the Ecctis name. Learn more at www.cambridgeinternational.org/recognition School feedback: ‘The depth of knowledge displayed by the best A Level students makes them prime targets for America’s Ivy League universities.’ Feedback from: Yale University, USA Back to contents page www.cambridgeinternational.org/alevel 6  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Why choose this syllabus? Supporting teachers We provide a wide range of resources, detailed guidance, innovative training and professional development so that you can give your students the best possible preparation for Cambridge International AS & A Level. To find out which resources are available for each syllabus go to www.cambridgeinternational.org/support The School Support Hub is our secure online site for Cambridge teachers where you can find the resources you need to deliver our programmes. You can also keep up to date with your subject and the global Cambridge community through our online discussion forums. Find out more at www.cambridgeinternational.org/support Support for Cambridge International AS & A Level Planning and Teaching and Learning and revision Results preparation assessment Example candidate Candidate Results Schemes of work Endorsed resources responses Service Specimen papers Online forums Past papers and Principal examiner Syllabuses Support for mark schemes reports for teachers Teacher guides coursework and Specimen paper speaking tests answers Sign up for email notifications about changes to syllabuses, including new and revised products and services at www.cambridgeinternational.org/syllabusupdates Professional development We support teachers through: Introductory Training – face-to-face or online Extension Training – face-to-face or online Enrichment Professional Development – face-to-face or online Find out more at www.cambridgeinternational.org/events Cambridge Professional Development Qualifications Find out more at www.cambridgeinternational.org/profdev Supporting exams officers We provide comprehensive support and guidance for all Cambridge exams officers. Find out more at: www.cambridgeinternational.org/eoguide Back to contents page www.cambridgeinternational.org/alevel 7  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027 2 Syllabus overview Aims The aims describe the purposes of a course based on this syllabus. The aims are to enable students to: acquire knowledge and understanding and develop practical skills, including efficient, accurate and safe scientific practices learn to apply the scientific method, while developing an awareness of the limitations of scientific theories and models develop skills in data analysis, evaluation and drawing conclusions, cultivating attitudes relevant to science such as objectivity, integrity, enquiry, initiative and inventiveness develop effective scientific communication skills, using appropriate terminology and scientific conventions understand their responsibility to others/society and to care for the environment enjoy science and develop an informed interest in the subject that may lead to further study. Cambridge Assessment International Education is an education organisation and politically neutral. The contents of this syllabus, examination papers and associated materials do not endorse any political view. We endeavour to treat all aspects of the exam process neutrally. Back to contents page www.cambridgeinternational.org/alevel 8  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Syllabus overview Content overview Candidates for Cambridge International AS Level Biology study the following topics: 1 Cell structure 2 Biological molecules 3 Enzymes 4 Cell membranes and transport 5 The mitotic cell cycle 6 Nucleic acids and protein synthesis 7 Transport in plants 8 Transport in mammals 9 Gas exchange 10 Infectious diseases 11 Immunity AS Level candidates also study practical skills. Candidates for Cambridge International A Level Biology study the AS topics and the following topics: 12 Energy and respiration 13 Photosynthesis 14 Homeostasis 15 Control and coordination 16 Inheritance 17 Selection and evolution 18 Classification, biodiversity and conservation 19 Genetic technology A Level candidates also study practical skills. School feedback: ‘Cambridge International AS & A Levels prepare students well for university because they’ve learnt to go into a subject in considerable depth. There’s that ability to really understand the depth and richness and the detail of a subject. It’s a wonderful preparation for what they are going to face at university.’ Feedback from: US Higher Education Advisory Council Back to contents page www.cambridgeinternational.org/alevel 9  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Syllabus overview Assessment overview Paper 1 Paper 4 Multiple Choice 1 hour 15 minutes A Level Structured Questions 2 hours 40 marks 100 marks 40 Multiple-choice questions Structured questions Questions are based on the AS Level syllabus Questions are based on the A Level syllabus content. content; knowledge of material from the AS Level Externally assessed syllabus content will be required. 31% of the AS Level Externally assessed 15.5% of the A Level 38.5% of the A Level Paper 2 Paper 5 AS Level Structured Questions Planning, Analysis and Evaluation 1 hour 15 minutes 1 hour 15 minutes 60 marks 30 marks Structured questions Questions are based on the practical skills of Questions are based on the AS Level syllabus planning, analysis and evaluation. content. The context of the questions may be outside the Externally assessed syllabus content. 46% of the AS Level Externally assessed 23% of the A Level 11.5% of the A Level Paper 3 Advanced Practical Skills 2 hours 40 marks Practical work and structured questions Questions are based on the practical skills in the Practical assessment section of the syllabus. The context of the questions may be outside the syllabus content. Externally assessed 23% of the AS Level 11.5% of the A Level Information on availability is in the Before you start section. Back to contents page www.cambridgeinternational.org/alevel 10  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Syllabus overview There are three routes for Cambridge International AS & A Level Biology: Route Paper 1 Paper 2 Paper 3 Paper 4 Paper 5 1 AS Level only (Candidates take all AS components yes yes yes in the same exam series) 2 A Level (staged over two years) Year 1 AS Level* yes yes yes Year 2 Complete the A Level yes yes 3 A Level (Candidates take all components in yes yes yes yes yes the same exam series) * Candidates carry forward their AS Level result subject to the rules and time limits described in the Cambridge Handbook. See Making entries for more information on carry forward of results. Candidates following an AS Level route will be eligible for grades a–e. Candidates following an A Level route are eligible for grades A*–E. Back to contents page www.cambridgeinternational.org/alevel 11  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Syllabus overview Assessment objectives The assessment objectives (AOs) are: AO1 Knowledge and understanding Candidates should be able to demonstrate knowledge and understanding of: scientific phenomena, facts, laws, definitions, concepts and theories scientific vocabulary, terminology and conventions (including symbols, quantities and units) scientific instruments and apparatus, including techniques of operation and aspects of safety scientific quantities and their determination scientific and technological applications with their social, economic and environmental implications. AO2 Handling, applying and evaluating information Candidates should be able to handle, apply and evaluate information, in words or using other forms of presentation (e.g. symbols, graphical or numerical) to: locate, select, organise and present information from a variety of sources translate information from one form to another manipulate numerical and other data use information to identify patterns, report trends and draw conclusions give reasoned explanations for phenomena, patterns and relationships make predictions and construct arguments to support hypotheses apply knowledge, including principles, to new situations evaluate information and hypotheses demonstrate an awareness of the limitations of biological theories and models solve problems. AO3 Experimental skills and investigations Candidates should be able to: plan experiments and investigations collect, record and present observations, measurements and estimates analyse and interpret experimental data to reach conclusions evaluate methods and quality of experimental data and suggest possible improvements to experiments. Back to contents page www.cambridgeinternational.org/alevel 12  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Syllabus overview Weighting for assessment objectives The approximate weightings allocated to each of the assessment objectives (AOs) are summarised below. Assessment objectives as a percentage of each qualification Assessment objective Weighting in AS Level Weighting in A Level % % AO1 Knowledge and understanding 40 40 AO2 Handling, applying and evaluating information 40 40 AO3 Experimental skills and investigations 20 20 Total 100 100 Assessment objectives as a percentage of each component Assessment objective Weighting in components % Paper 1 Paper 2 Paper 3 Paper 4 Paper 5 AO1 Knowledge and understanding 50 50 0 50 0 AO2 Handling, applying and evaluating information 50 50 0 50 0 AO3 Experimental skills and investigations 0 0 100 0 100 Total 100 100 100 100 100 Back to contents page www.cambridgeinternational.org/alevel 13  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027 3 Subject content Candidates for Cambridge International AS Level should study topics 1–11. Candidates for Cambridge International A Level should study all topics. The content of the AS Level learning outcomes are assumed knowledge for the A Level components. Teachers should refer to the social, environmental, economic and technological aspects of biology wherever possible throughout the syllabus. Some examples are included in the syllabus and teachers should encourage learners to apply the principles of these examples to other situations introduced in the course. Teachers should illustrate concepts and content with examples taken from a wide range of organisms. Everything we know about biology has been learned through practical investigation. Learners also find practical work motivating and interesting, and it can help them to understand abstract theoretical concepts. Cambridge International expects that practical activities will underpin the teaching of the whole syllabus. The syllabus content for practical skills is in the Practical assessment section. Teachers should ensure that candidates are prepared for the assessment of theory learning outcomes and practical skills. This syllabus gives you the flexibility to design a course that will interest, challenge and engage your learners. Where appropriate you are responsible for selecting suitable subject contexts, resources and examples to support your learners’ study. These should be appropriate for the learners’ age, cultural background and learning context as well as complying with your school policies and local legal requirements. Support for teaching practical skills for these qualifications can be found on the School Support Hub www.cambridgeinternational.org/support Back to contents page www.cambridgeinternational.org/alevel 14  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content AS Level subject content 1 Cell structure All organisms are composed of cells. Knowledge of the structure and function of cells underpins much of biology. The fundamental differences between eukaryotic and prokaryotic cells are explored and provide useful biological background for the topic on Infectious diseases (Topic 10). Viruses are introduced as non- cellular structures, which gives candidates the opportunity to consider whether cells are the basic unit of life. The use of light microscopes is a fundamental skill that is developed in this topic and applied throughout several other topics of the syllabus. 1.1 The microscope in cell Learning outcomes studies Candidates should be able to: 1 make temporary preparations of cellular material suitable for viewing with a light microscope 2 draw cells from microscope slides and photomicrographs 3 calculate magnifications of images and actual sizes of specimens from drawings, photomicrographs and electron micrographs (scanning and transmission) 4 use an eyepiece graticule and stage micrometer scale to make measurements and use the appropriate units, millimetre (mm), micrometre (µm) and nanometre (nm) 5 define resolution and magnification and explain the differences between these terms, with reference to light microscopy and electron microscopy 1.2 Cells as the basic units of Learning outcomes living organisms Candidates should be able to: 1 recognise organelles and other cell structures found in eukaryotic cells and outline their structures and functions, limited to: cell surface membrane nucleus, nuclear envelope and nucleolus rough endoplasmic reticulum smooth endoplasmic reticulum Golgi body (Golgi apparatus or Golgi complex) mitochondria (including the presence of small circular DNA) ribosomes (80S in the cytoplasm and 70S in chloroplasts and mitochondria) lysosomes centrioles and microtubules cilia microvilli chloroplasts (including the presence of small circular DNA) cell wall plasmodesmata large permanent vacuole and tonoplast of plant cells continued Back to contents page www.cambridgeinternational.org/alevel 15  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content 1.2 Cells as the basic units of Learning outcomes living organisms (continued) Candidates should be able to: 2 describe and interpret photomicrographs, electron micrographs and drawings of typical plant and animal cells 3 compare the structure of typical plant and animal cells 4 state that cells use ATP from respiration for energy-requiring processes 5 outline key structural features of a prokaryotic cell as found in a typical bacterium, including: unicellular generally 1–5 µm diameter peptidoglycan cell walls circular DNA 70S ribosomes absence of organelles surrounded by double membranes 6 compare the structure of a prokaryotic cell as found in a typical bacterium with the structures of typical eukaryotic cells in plants and animals 7 state that all viruses are non-cellular structures with a nucleic acid core (either DNA or RNA) and a capsid made of protein, and that some viruses have an outer envelope made of phospholipids Back to contents page www.cambridgeinternational.org/alevel 16  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content 2 Biological molecules This topic introduces carbohydrates, lipids and proteins: organic molecules that are important in cells. Nucleic acids, another class of biological molecule, are covered in Topic 6. All of these molecules are based on the versatile element carbon. This topic explains how carbohydrates, lipids and proteins, which have a great diversity of function in organisms, are assembled from smaller organic molecules such as glucose, amino acids, glycerol and fatty acids. The emphasis in this topic is on the relationship between molecular structures and their functions. Some of these ideas are continued in other topics, for example, the functions of haemoglobin in gas transport in Transport in mammals (Topic 8), phospholipids in membranes in Cell membranes and transport (Topic 4) and antibodies in Immunity (Topic 11). Life as we know it would not be possible without water. Understanding the properties of this extraordinary molecule is an essential part of any study of biological molecules. Some of the roles of water are in this topic, others are in Topics 4, 7, 8, 12, 13 and 14. 2.1 Testing for biological Learning outcomes molecules Candidates should be able to: 1 describe and carry out the Benedict’s test for reducing sugars, the iodine test for starch, the emulsion test for lipids and the biuret test for proteins 2 describe and carry out a semi-quantitative Benedict’s test on a reducing sugar solution by standardising the test and using the results (time to first colour change or comparison to colour standards) to estimate the concentration 3 describe and carry out a test to identify the presence of non-reducing sugars, using acid hydrolysis and Benedict’s solution 2.2 Carbohydrates and lipids Learning outcomes Candidates should be able to: 1 describe and draw the ring forms of α-glucose and β-glucose 2 define the terms monomer, polymer, macromolecule, monosaccharide, disaccharide and polysaccharide 3 state the role of covalent bonds in joining smaller molecules together to form polymers 4 state that glucose, fructose and maltose are reducing sugars and that sucrose is a non-reducing sugar 5 describe the formation of a glycosidic bond by condensation, with reference to disaccharides, including sucrose, and polysaccharides continued Back to contents page www.cambridgeinternational.org/alevel 17  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content 2.2 Carbohydrates and lipids Learning outcomes continued Candidates should be able to: 6 describe the breakage of a glycosidic bond in polysaccharides and disaccharides by hydrolysis, with reference to the non-reducing sugar test 7 describe the molecular structure of the polysaccharides starch (amylose and amylopectin) and glycogen and relate their structures to their functions in living organisms 8 describe the molecular structure of the polysaccharide cellulose and outline how the arrangement of cellulose molecules contributes to the function of plant cell walls 9 state that triglycerides are non-polar hydrophobic molecules and describe the molecular structure of triglycerides with reference to fatty acids (saturated and unsaturated), glycerol and the formation of ester bonds 10 relate the molecular structure of triglycerides to their functions in living organisms 11 describe the molecular structure of phospholipids with reference to their hydrophilic (polar) phosphate heads and hydrophobic (non-polar) fatty acid tails 2.3 Proteins Learning outcomes Candidates should be able to: 1 describe and draw the general structure of an amino acid and the formation and breakage of a peptide bond 2 explain the meaning of the terms primary structure, secondary structure, tertiary structure and quaternary structure of proteins 3 describe the types of interaction that hold protein molecules in shape: hydrophobic interactions hydrogen bonding ionic bonding covalent bonding, including disulfide bonds 4 state that globular proteins are generally soluble and have physiological roles and fibrous proteins are generally insoluble and have structural roles 5 describe the structure of a molecule of haemoglobin as an example of a globular protein, including the formation of its quaternary structure from two alpha (α) chains (α–globin), two beta (β) chains (β–globin) and a haem group 6 relate the structure of haemoglobin to its function, including the importance of iron in the haem group 7 describe the structure of a molecule of collagen as an example of a fibrous protein, and the arrangement of collagen molecules to form collagen fibres 8 relate the structures of collagen molecules and collagen fibres to their function Back to contents page www.cambridgeinternational.org/alevel 18  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content 2.4 Water Learning outcomes Candidates should be able to: 1 explain how hydrogen bonding occurs between water molecules and relate the properties of water to its roles in living organisms, limited to solvent action, high specific heat capacity and latent heat of vaporisation Back to contents page www.cambridgeinternational.org/alevel 19  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content 3 Enzymes Enzymes are essential for life to exist. The mode of action of enzymes and the factors that affect their activity are explored in this topic. Prior knowledge for this topic is an understanding that an enzyme is a biological catalyst that increases the rate of a reaction and remains unchanged when the reaction is complete. There are many opportunities in this topic for candidates to gain experience of carrying out practical investigations and analysing, interpreting and evaluating their results. 3.1 Mode of action of enzymes Learning outcomes Candidates should be able to: 1 state that enzymes are globular proteins that catalyse reactions inside cells (intracellular enzymes) or are secreted to catalyse reactions outside cells (extracellular enzymes) 2 explain the mode of action of enzymes in terms of an active site, enzyme–substrate complex, lowering of activation energy and enzyme specificity, including the lock-and-key hypothesis and the induced-fit hypothesis 3 investigate the progress of enzyme-catalysed reactions by measuring rates of formation of products using catalase and rates of disappearance of substrate using amylase 4 outline the use of a colorimeter for measuring the progress of enzyme-catalysed reactions that involve colour changes 3.2 Factors that affect enzyme Learning outcomes action Candidates should be able to: 1 investigate and explain the effects of the following factors on the rate of enzyme-catalysed reactions: temperature pH (using buffer solutions) enzyme concentration substrate concentration inhibitor concentration 2 explain that the maximum rate of reaction (Vmax) is used to derive the Michaelis–Menten constant (Km), which is used to compare the affinity of different enzymes for their substrates 3 explain the effects of reversible inhibitors, both competitive and non-competitive, on enzyme activity 4 investigate the difference in activity between an enzyme immobilised in alginate and the same enzyme free in solution, and state the advantages of using immobilised enzymes Back to contents page www.cambridgeinternational.org/alevel 20  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content 4 Cell membranes and transport The fluid mosaic model, introduced in 1972, describes the way in which biological molecules are arranged to form cell membranes. The model continues to be modified as understanding improves of the ways in which substances cross membranes, how cells interact and how cells respond to signals. The model also provides the basis for our understanding of passive and active movement of molecules and ions between cells and their surroundings, cell-to-cell interactions and long-distance cell signalling. Investigating the effects of different factors on diffusion, osmosis and membrane permeability involves an understanding of the properties of phospholipids and proteins covered in Biological molecules (Topic 2). 4.1 Fluid mosaic membranes Learning outcomes Candidates should be able to: 1 describe the fluid mosaic model of membrane structure with reference to the hydrophobic and hydrophilic interactions that account for the formation of the phospholipid bilayer and the arrangement of proteins 2 describe the arrangement of cholesterol, glycolipids and glycoproteins in cell surface membranes 3 describe the roles of phospholipids, cholesterol, glycolipids, proteins and glycoproteins in cell surface membranes, with reference to stability, fluidity, permeability, transport (carrier proteins and channel proteins), cell signalling (cell surface receptors) and cell recognition (cell surface antigens – see 11.1.2) 4 outline the main stages in the process of cell signalling leading to specific responses: secretion of specific chemicals (ligands) from cells transport of ligands to target cells binding of ligands to cell surface receptors on target cells 4.2 Movement into and out of Learning outcomes cells Candidates should be able to: 1 describe and explain the processes of simple diffusion, facilitated diffusion, osmosis, active transport, endocytosis and exocytosis 2 investigate simple diffusion and osmosis using plant tissue and non-living materials, including dialysis (Visking) tubing and agar 3 illustrate the principle that surface area to volume ratios decrease with increasing size by calculating surface areas and volumes of simple 3-D shapes (as shown in the Mathematical requirements) 4 investigate the effect of changing surface area to volume ratio on diffusion using agar blocks of different sizes continued Back to contents page www.cambridgeinternational.org/alevel 21  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content 4.2 Movement into and out of Learning outcomes cells continued Candidates should be able to: 5 investigate the effects of immersing plant tissues in solutions of different water potentials, using the results to estimate the water potential of the tissues 6 explain the movement of water between cells and solutions in terms of water potential and explain the different effects of the movement of water on plant cells and animal cells (knowledge of solute potential and pressure potential is not expected) Back to contents page www.cambridgeinternational.org/alevel 22  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content 5 The mitotic cell cycle When body cells reach a certain size they divide into two cells. Nuclear division occurs first, followed by division of the cytoplasm. The mitotic cell cycle of eukaryotes involves DNA replication followed by nuclear division. This ensures the genetic uniformity of all daughter cells. 5.1 Replication and division of Learning outcomes nuclei and cells Candidates should be able to: 1 describe the structure of a chromosome, limited to: DNA histone proteins sister chromatids centromere telomeres 2 explain the importance of mitosis in the production of genetically identical daughter cells during: growth of multicellular organisms replacement of damaged or dead cells repair of tissues by cell replacement asexual reproduction 3 outline the mitotic cell cycle, including: interphase (growth in G1 and G2 phases and DNA replication in S phase) mitosis cytokinesis 4 outline the role of telomeres in preventing the loss of genes from the ends of chromosomes during DNA replication 5 outline the role of stem cells in cell replacement and tissue repair by mitosis 6 explain how uncontrolled cell division can result in the formation of a tumour 5.2 Chromosome behaviour in Learning outcomes mitosis Candidates should be able to: 1 describe the behaviour of chromosomes in plant and animal cells during the mitotic cell cycle and the associated behaviour of the nuclear envelope, the cell surface membrane and the spindle (names of the main stages of mitosis are expected: prophase, metaphase, anaphase and telophase) 2 interpret photomicrographs, diagrams and microscope slides of cells in different stages of the mitotic cell cycle and identify the main stages of mitosis Back to contents page www.cambridgeinternational.org/alevel 23  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content 6 Nucleic acids and protein synthesis Nucleic acids have roles in the storage and retrieval of genetic information and in the use of this information to synthesise polypeptides. DNA is the molecule of heredity and is an extremely stable molecule that cells replicate with great accuracy. The genetic code explains how the sequence of nucleotides in DNA and messenger RNA (mRNA) determines the sequence of amino acids that make up a polypeptide. In eukaryotes this involves the processes of transcription in the nucleus to produce mRNA, followed by translation in the cytoplasm to produce polypeptides. 6.1 Structure of nucleic acids Learning outcomes and replication of DNA Candidates should be able to: 1 describe the structure of nucleotides, including the phosphorylated nucleotide ATP (structural formulae are not expected) 2 state that the bases adenine and guanine are purines with a double ring structure, and that the bases cytosine, thymine and uracil are pyrimidines with a single ring structure (structural formulae for bases are not expected) 3 describe the structure of a DNA molecule as a double helix, including: the importance of complementary base pairing between the 5′ to 3′ strand and the 3′ to 5′ strand (antiparallel strands) differences in hydrogen bonding between C–G and A–T base pairs linking of nucleotides by phosphodiester bonds 4 describe the semi-conservative replication of DNA during the S phase of the cell cycle, including: the roles of DNA polymerase and DNA ligase (knowledge of other enzymes in DNA replication in cells and different types of DNA polymerase is not expected) the differences between leading strand and lagging strand replication as a consequence of DNA polymerase adding nucleotides only in a 5′ to 3′ direction 5 describe the structure of an RNA molecule, using the example of messenger RNA (mRNA) 6.2 Protein synthesis Learning outcomes Candidates should be able to: 1 state that a polypeptide is coded for by a gene and that a gene is a sequence of nucleotides that forms part of a DNA molecule 2 describe the principle of the universal genetic code in which different triplets of DNA bases either code for specific amino acids or correspond to start and stop codons continued Back to contents page www.cambridgeinternational.org/alevel 24  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content 6.2 Protein synthesis continued Learning outcomes Candidates should be able to: 3 describe how the information in DNA is used during transcription and translation to construct polypeptides, including the roles of: RNA polymerase messenger RNA (mRNA) codons transfer RNA (tRNA) anticodons ribosomes 4 state that the strand of a DNA molecule that is used in transcription is called the transcribed or template strand and that the other strand is called the non-transcribed strand 5 explain that, in eukaryotes, the RNA molecule formed following transcription (primary transcript) is modified by the removal of non-coding sequences (introns) and the joining together of coding sequences (exons) to form mRNA 6 state that a gene mutation is a change in the sequence of base pairs in a DNA molecule that may result in an altered polypeptide 7 explain that a gene mutation is a result of substitution or deletion or insertion of nucleotides in DNA and outline how each of these types of mutation may affect the polypeptide produced Back to contents page www.cambridgeinternational.org/alevel 25  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content 7 Transport in plants Flowering plants do not have compact bodies like those of many animals. Leaves and extensive root systems spread out to obtain the light energy, carbon dioxide, mineral ions and water that plants gain from their environment to make organic molecules, such as sugars and amino acids. Transport systems in plants move substances from where they are absorbed or produced to where they are stored or used. 7.1 Structure of transport tissues Learning outcomes Candidates should be able to: 1 draw plan diagrams of transverse sections of stems, roots and leaves of herbaceous dicotyledonous plants from microscope slides and photomicrographs 2 describe the distribution of xylem and phloem in transverse sections of stems, roots and leaves of herbaceous dicotyledonous plants 3 draw and label xylem vessel elements, phloem sieve tube elements and companion cells from microscope slides, photomicrographs and electron micrographs 4 relate the structure of xylem vessel elements, phloem sieve tube elements and companion cells to their functions 7.2 Transport mechanisms Learning outcomes Candidates should be able to: 1 state that some mineral ions and organic compounds can be transported within plants dissolved in water 2 describe the transport of water from the soil to the xylem through the: apoplast pathway, including reference to lignin and cellulose symplast pathway, including reference to the endodermis, Casparian strip and suberin 3 explain that transpiration involves the evaporation of water from the internal surfaces of leaves followed by diffusion of water vapour to the atmosphere 4 explain how hydrogen bonding of water molecules is involved with movement of water in the xylem by cohesion-tension in transpiration pull and by adhesion to cellulose in cell walls 5 make annotated drawings of transverse sections of leaves from xerophytic plants to explain how they are adapted to reduce water loss by transpiration 6 state that assimilates dissolved in water, such as sucrose and amino acids, move from sources to sinks in phloem sieve tubes 7 explain how companion cells transfer assimilates to phloem sieve tubes, with reference to proton pumps and cotransporter proteins 8 explain mass flow in phloem sieve tubes down a hydrostatic pressure gradient from source to sink Back to contents page www.cambridgeinternational.org/alevel 26  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content 8 Transport in mammals As animals become larger, more complex and more active, transport systems become essential to supply nutrients to, and remove waste from, individual cells. Mammals are far more active than plants and require much greater supplies of oxygen. This is transported by haemoglobin inside red blood cells. 8.1 The circulatory system Learning outcomes Candidates should be able to: 1 state that the mammalian circulatory system is a closed double circulation consisting of a heart, blood and blood vessels including arteries, arterioles, capillaries, venules and veins 2 describe the functions of the main blood vessels of the pulmonary and systemic circulations, limited to pulmonary artery, pulmonary vein, aorta and vena cava 3 recognise arteries, veins and capillaries from microscope slides, photomicrographs and electron micrographs and make plan diagrams showing the structure of arteries and veins in transverse section (TS) and longitudinal section (LS) 4 explain how the structure of muscular arteries, elastic arteries, veins and capillaries are each related to their functions 5 recognise and draw red blood cells, monocytes, neutrophils and lymphocytes from microscope slides, photomicrographs and electron micrographs 6 state that water is the main component of blood and tissue fluid and relate the properties of water to its role in transport in mammals, limited to solvent action and high specific heat capacity 7 state the functions of tissue fluid and describe the formation of tissue fluid in a capillary network Back to contents page www.cambridgeinternational.org/alevel 27  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content 8.2 Transport of oxygen and Learning outcomes carbon dioxide Candidates should be able to: 1 describe the role of red blood cells in transporting oxygen and carbon dioxide with reference to the roles of: haemoglobin carbonic anhydrase the formation of haemoglobinic acid the formation of carbaminohaemoglobin 2 describe the chloride shift and explain the importance of the chloride shift 3 describe the role of plasma in the transport of carbon dioxide 4 describe and explain the oxygen dissociation curve of adult haemoglobin 5 explain the importance of the oxygen dissociation curve at partial pressures of oxygen in the lungs and in respiring tissues 6 describe the Bohr shift and explain the importance of the Bohr shift 8.3 The heart Learning outcomes Candidates should be able to: 1 describe the external and internal structure of the mammalian heart 2 explain the differences in the thickness of the walls of the: atria and ventricles left ventricle and right ventricle 3 describe the cardiac cycle, with reference to the relationship between blood pressure changes during systole and diastole and the opening and closing of valves 4 explain the roles of the sinoatrial node, the atrioventricular node and the Purkyne tissue in the cardiac cycle (knowledge of nervous and hormonal control is not expected) Back to contents page www.cambridgeinternational.org/alevel 28  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content 9 Gas exchange The gas exchange system is responsible for the uptake of oxygen into the blood and the excretion of carbon dioxide. An understanding of this system shows how cells, tissues and organs function together to exchange these gases between the blood and the environment. 9.1 The gas exchange system Learning outcomes Candidates should be able to: 1 describe the structure of the human gas exchange system, limited to: lungs trachea bronchi bronchioles alveoli capillary network 2 describe the distribution in the gas exchange system of cartilage, ciliated epithelium, goblet cells, squamous epithelium of alveoli, smooth muscle and capillaries 3 recognise cartilage, ciliated epithelium, goblet cells, squamous epithelium of alveoli, smooth muscle and capillaries in microscope slides, photomicrographs and electron micrographs 4 recognise trachea, bronchi, bronchioles and alveoli in microscope slides, photomicrographs and electron micrographs and make plan diagrams of transverse sections of the walls of the trachea and bronchus 5 describe the functions of ciliated epithelial cells, goblet cells and mucous glands in maintaining the health of the gas exchange system 6 describe the functions in the gas exchange system of cartilage, smooth muscle, elastic fibres and squamous epithelium 7 describe gas exchange between air in the alveoli and blood in the capillaries Back to contents page www.cambridgeinternational.org/alevel 29  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content 10 Infectious diseases The infectious diseases studied in this topic are caused by pathogens that are transmitted from one human host to another. Some, like Plasmodium that causes malaria, are transmitted by vectors, but there are many other methods of transmission, such as through water and food or during sexual activity. An understanding of the biology of the pathogen and its mode of transmission is essential if the disease is to be controlled and ultimately prevented. 10.1 Infectious diseases Learning outcomes Candidates should be able to: 1 state that infectious diseases are caused by pathogens and are transmissible 2 state the name and type of pathogen that causes each of the following diseases: cholera – caused by the bacterium Vibrio cholerae malaria – caused by the protoctists Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale and Plasmodium vivax tuberculosis (TB) – caused by the bacteria Mycobacterium tuberculosis and Mycobacterium bovis HIV/AIDS – caused by the human immunodeficiency virus (HIV) 3 explain how cholera, malaria, TB and HIV are transmitted 4 discuss the biological, social and economic factors that need to be considered in the prevention and control of cholera, malaria, TB and HIV (details of the life cycle of the malarial parasite are not expected) 10.2 Antibiotics Learning outcomes Candidates should be able to: 1 outline how penicillin acts on bacteria and why antibiotics do not affect viruses 2 discuss the consequences of antibiotic resistance and the steps that can be taken to reduce its impact Back to contents page www.cambridgeinternational.org/alevel 30  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content 11 Immunity An understanding of the immune system shows how cells and molecules function together to protect the body against infectious diseases and how, after an initial infection, the body is protected from subsequent infections by the same pathogen. Phagocytosis is an immediate non-specific part of the immune system, while the actions of lymphocytes provide effective defence against specific pathogens. 11.1 The immune system Learning outcomes Candidates should be able to: 1 describe the mode of action of phagocytes (macrophages and neutrophils) 2 explain what is meant by an antigen (see 4.1.3) and state the difference between self antigens and non-self antigens 3 describe the sequence of events that occurs during a primary immune response with reference to the roles of: macrophages B-lymphocytes, including plasma cells T-lymphocytes, limited to T-helper cells and T-killer cells 4 explain the role of memory cells in the secondary immune response and in long-term immunity 11.2 Antibodies and vaccination Learning outcomes Candidates should be able to: 1 relate the molecular structure of antibodies to their functions 2 outline the hybridoma method for the production of monoclonal antibodies 3 outline the principles of using monoclonal antibodies in the diagnosis of disease and in the treatment of disease 4 describe the differences between active immunity and passive immunity and between natural immunity and artificial immunity 5 explain that vaccines contain antigens that stimulate immune responses to provide long-term immunity 6 explain how vaccination programmes can help to control the spread of infectious diseases Back to contents page www.cambridgeinternational.org/alevel 31  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content A Level subject content 12 Energy and respiration Energy is a fundamental concept in biology. All living organisms require a source of cellular energy to drive their various activities. All organisms respire by using enzyme-catalysed reactions to release energy from energy-rich molecules such as glucose and fatty acids and transfer that energy to ATP. ATP is the universal energy currency of cells. In eukaryotes, aerobic respiration occurs in mitochondria. The practical activities in this topic give opportunities for candidates to plan investigations, analyse and interpret data and evaluate experimental procedures and the quality of the data collected. 12.1 Energy Learning outcomes Candidates should be able to: 1 outline the need for energy in living organisms, as illustrated by active transport, movement and anabolic reactions, such as those occurring in DNA replication and protein synthesis 2 describe the features of ATP that make it suitable as the universal energy currency 3 state that ATP is synthesised by: transfer of phosphate in substrate-linked reactions chemiosmosis in membranes of mitochondria and chloroplasts 4 explain the relative energy values of carbohydrates, lipids and proteins as respiratory substrates 5 state that the respiratory quotient (RQ) is the ratio of the number of molecules of carbon dioxide produced to the number of molecules of oxygen taken in, as a result of respiration 6 calculate RQ values of different respiratory substrates from equations for respiration 7 describe and carry out investigations, using simple respirometers, to determine the RQ of germinating seeds or small invertebrates (e.g. blowfly larvae) Back to contents page www.cambridgeinternational.org/alevel 32  Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027. Subject content 12.2 Respiration Learning outcomes Candidates should be able to: 1 State where each of the four stages in aerobic respiration occurs in eukaryotic cells: glycolysis in the cytoplasm link reaction in the mitochondrial matrix Krebs cycle in the mitochondrial matrix oxidative phosphorylation on the inner membrane of mitochondria 2 outline glycolysis as phosphorylation of glucose and the subsequent splitting of fructose 1,6-bisphosphate (6C) into two triose phosphate molecules (3C), which are then further oxidised to pyruvate (3C), with the production of ATP and reduced NAD 3 explain that, when oxygen is available, pyruvate enters mitochondria to take part in the link reaction 4 describe the link reaction, including the role of coenzyme A in the transfer of acetyl (2C) groups 5 outline the Krebs cycle, explaining that oxaloacetate (4C) acts as an acceptor of the 2C fragment from acetyl coenzyme A to form citrate (6C), which is converted back to oxaloacetate in a series of small steps 6 explain that reactions in the Krebs cycle involve decarboxylation and dehydrogenation and the reduction of the coenzymes NAD and FAD 7 describe the role of NAD and FAD in transferring hydrogen to carriers in the inner mitochondrial membrane 8 explain that during oxidative phosphorylation: hydrogen atoms split into protons and energetic electrons energetic electrons release energy as they pass through the electron transport chain (details of carriers are not expected)