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2. Organisation

Principles of organisation

1 lesson
2.1 Cells, tissues, organs and organ systems How large multicellular organisms are organised: cells form tissues, tissues form organs, organs form organ systems, and organ systems make up the whole organism, with examples from humans and plants. AQA Edexcel OCR

Enzymes and digestion

6 lessons
2.2 Enzymes and the lock and key model What enzymes are, how the shape of the active site makes each enzyme specific to one substrate, the lock and key model, and what happens when an enzyme is denatured. AQA Edexcel OCR 2.3 Factors affecting enzyme activity How temperature, pH, substrate concentration and enzyme concentration change the rate of an enzyme-controlled reaction, what an optimum is, and how to calculate a rate of reaction. AQA Edexcel OCR 2.4 Required practical: pH and amylase The required practical for the effect of pH on amylase: the starch and iodine continuous sampling method, variables, how to calculate rate as 1000 divided by time, and how to make the results more accurate. AQA Edexcel OCR 2.5 The digestive system and digestive enzymes The organs of the digestive system, the three groups of digestive enzymes (carbohydrases, proteases and lipases), where they are made and what they produce, and how bile helps digestion. AQA Edexcel OCR 2.6 Required practical: food tests How to test foods for starch, reducing sugars, protein and lipids using iodine, Benedict's solution, biuret reagent and Sudan III or the ethanol emulsion test, with the colour changes, safety and how to prepare a food sample. AQA Edexcel OCR 2.7 Measuring the energy in food (calorimetry) Edexcel core practical: burning a food sample under a boiling tube of water to measure the energy it contains, calculating energy with mass of water x 4.2 x temperature rise, and why the result is lower than the true value. Separate only Edexcel

The heart and lungs

5 lessons
2.8 The lungs and gas exchange The structure of the lungs, from the trachea to the alveoli, and how alveoli are adapted for gas exchange: a large surface area, thin walls, a good blood supply and ventilation keep oxygen and carbon dioxide diffusing quickly. AQA Edexcel OCR 2.9 The heart How the double circulatory system works, the four chambers of the heart, its valves and major blood vessels, why the left ventricle has the thickest wall, the coronary arteries and the pacemaker. AQA Edexcel OCR 2.10 Heart rate and cardiac output Edexcel: calculating cardiac output from stroke volume and heart rate, rearranging the equation, measuring heart rate from the pulse, and why cardiac output rises during exercise. Edexcel 2.11 Blood vessels How the structures of arteries, veins and capillaries suit their jobs: thick elastic walls for high pressure, valves and wide lumens for low pressure, and walls one cell thick for exchange, plus how to calculate the rate of blood flow. AQA Edexcel OCR 2.12 Blood The four parts of the blood: plasma, red blood cells, white blood cells and platelets, what each does, how red blood cells are adapted to carry oxygen, and how to recognise each in a blood smear. AQA Edexcel OCR

Non-communicable disease

3 lessons
2.13 Coronary heart disease and its treatment How fatty deposits in the coronary arteries cause coronary heart disease, and how it and other heart problems are treated: stents, statins, valve replacement, transplants, artificial hearts and lifestyle changes, with their advantages and disadvantages. AQA Edexcel OCR 2.14 Health, lifestyle and risk factors What health is, communicable and non-communicable diseases, how diseases interact, the main risk factors (diet, exercise, smoking, alcohol, carcinogens), correlation and causation, BMI and waist:hip ratio, and the costs of disease. AQA Edexcel OCR 2.15 Cancer Cancer as uncontrolled cell growth and division caused by changes in cells, the difference between benign and malignant tumours, how cancers spread to form secondary tumours, and the lifestyle and genetic risk factors. AQA Edexcel OCR

Plant tissues and transport

5 lessons
2.16 Plant tissues and the leaf The leaf as a plant organ: the epidermis, palisade and spongy mesophyll, xylem, phloem and meristem tissues, and how guard cells open and close the stomata, with how each is adapted for photosynthesis and gas exchange. AQA Edexcel OCR 2.17 Root hair cells, xylem and phloem How root hair cells take up water by osmosis and mineral ions by active transport, and how xylem (dead, lignified, hollow tubes) and phloem (living sieve tube cells with sieve plates) are adapted to transport water and sugars. AQA Edexcel OCR 2.18 Transpiration and translocation How water moves through a plant in the transpiration stream, how light intensity, temperature, air movement and humidity change the rate of transpiration, and how sugars are moved by translocation in the phloem. AQA Edexcel OCR 2.19 Measuring transpiration with a potometer How to set up a bubble potometer, measure how far the air bubble moves, calculate the rate of water uptake (including volume from the tube radius), and why water uptake is not exactly the same as transpiration. AQA Edexcel OCR 2.20 Plants in extreme environments Edexcel: how leaf size and shape, the waxy cuticle and the number and position of stomata help plants such as cacti, marram grass and pine trees to survive hot, dry, windy or cold places by reducing water loss. Separate only Edexcel