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Topic 1

EDEXCEL IAL BIOLOGY

Specification 2025 - 2026

Unit 1

Biology Checklist – Topic 1: Molecules, Transport and Health

Topic 1 – Molecules, Transport and Health

Progress: 0%

1.1 Importance of Water

Explain the importance of water as a solvent in transport.

Include its dipole nature .

1.2 Carbohydrates

Distinguish between monosaccharides , disaccharides , and polysaccharides including glycogen and starch (amylose and amylopectin).

Relate the structures of mono-, di- and polysaccharides to their roles in providing and storing energy.

Note: β-glucose and cellulose are not required in this topic.

1.3 CORE PRACTICAL 1

Use a semi-quantitative method with Benedict’s reagent (reducing sugars) and iodine solution (starch) using colour standards .

1.4 Formation and Breakdown of Carbohydrates

Describe condensation reactions forming glycosidic bonds between monosaccharides to make disaccharides (maltose, sucrose, lactose) and polysaccharides (glycogen, amylose, amylopectin), and hydrolysis reversing them.

1.5 Lipids

Explain how a triglyceride is synthesised by condensation between glycerol and three fatty acids with formation of ester bonds .

Differentiate between saturated and unsaturated lipids.

1.6 Heart and Circulation

Explain why many animals require a heart and circulation (mass transport overcoming limits of diffusion ).

1.7 Structure of Blood Vessels

Relate the structures of capillaries , arteries , and veins to their functions.

1.8 Cardiac Cycle

Describe the cardiac cycle : atrial systole, ventricular systole, and cardiac diastole; link heart structure (incl. major vessels) to function.

Details of myogenic stimulation are not needed at IAS.

Recommended Additional Practical

Dissect a mammalian heart to investigate its structure.

1.9 Role of Haemoglobin

Explain the role of haemoglobin in transport of oxygen and carbon dioxide.

Interpret the oxygen dissociation curve , the Bohr effect , and compare fetal vs adult haemoglobin oxygen affinity.

1.10 Atherosclerosis

Describe the sequence leading to atherosclerosis : endothelial dysfunction → inflammatory response → plaque formation → raised blood pressure.

1.11 Blood Clotting Process

Outline the blood clotting process : thromboplastin release; prothrombin → thrombin; fibrinogen → fibrin; role in CVD .

1.12 Risk Factors for CVD

Explain how genetics, diet, high blood pressure, smoking, and inactivity increase risk of cardiovascular disease (CVD) .

1.13 Dietary Antioxidants and CVD

Understand the link between dietary antioxidants and CVD risk.

1.14 CORE PRACTICAL 2

Investigate the vitamin C content of food and drink.

1.15 Data Analysis on Health Risks

Analyse and interpret quantitative data on illness/mortality to determine health risks; distinguish correlation vs causation ; recognise conflicting evidence.

1.16 Evaluating Study Design

Evaluate study design for health risk factors: sample selection and sample size for valid, reliable data.

1.17 Perception of Risks

Explain why perceived risks can differ from actual risks (e.g. diet/lifestyle in heart disease) including under- and over-estimation.

1.18 Blood Cholesterol Levels

Analyse health significance of blood cholesterol , HDL and LDL levels.

Know evidence for a causal relationship between total/LDL cholesterol and CVD .

1.19 Using Scientific Knowledge to Reduce Risk

Apply scientific knowledge about diet (incl. obesity indicators : BMI, waist-to-hip ratio), exercise, and smoking to reduce risk of coronary heart disease .

1.20 Treatments for Cardiovascular Disease (CVD)

Explain benefits and risks of CVD treatments: antihypertensives , statins , anticoagulants , and platelet inhibitors .

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