Combined Science Synergy

    AQA
    GCSE

    Specification: 8465

    The AQA GCSE Combined Science Synergy specification covers 80 topics with 500 learning objectives (8465). Use the topic browser below to explore subtopics, exam tips, common mistakes, and key terminology for each area of the course.

    Starting AQA GCSE Combined Science Synergy this term? The whole specification is below, unit by unit.

    This subject will help you develop key knowledge and skills required for exam success.

    80

    Topics

    500

    Objectives

    0

    Exam Tips

    0

    Pitfalls

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    Key Features

    • Master key concepts
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    • Apply knowledge effectively

    About AQA GCSE Combined Science Synergy

    AQA GCSE Combined Science Synergy is a double award qualification that blends biology, chemistry and physics into a thematic, concept-led course. Instead of studying the three sciences separately, you explore big ideas such as 'Building blocks', 'Transport over larger distances' and 'Interactions with the environment', which helps you see how scientific principles connect across disciplines. The specification is structured around these overarching themes, with each topic linking to relevant practical skills and mathematical requirements.

    The course is designed for students who want a broad, coherent understanding of science without the depth of separate GCSEs. You will develop investigative and analytical skills through required practical activities, and learn to apply your knowledge to real-world contexts like health, energy and sustainability. Assessment is linear, with all exams taken at the end of Year 11, and the final grade is a double award (two GCSE grades) based on the combined performance across six papers.

    Assessment Structure

    This qualification is assessed through six written exam papers, each lasting 1 hour 45 minutes and worth 16.7% of the total marks. There are two papers for each of the three themes: Paper 1 and 2 cover 'Building blocks' and 'Transport over larger distances'; Paper 3 and 4 cover 'Interactions with the environment' and 'Interactions over small and large distances'; Paper 5 and 6 cover 'Movement and interactions' and 'Guiding spaceship Earth towards a sustainable future'. Each paper includes multiple-choice, structured, closed short answer and open response questions, with a mix of biology, chemistry and physics content. There is no coursework, but practical skills are assessed within the written exams, and students must complete a set of required practical activities. The total mark across all papers determines the double award grade, which is reported as two GCSE grades (e.g., 9-9, 8-7).

    Why Choose AQA?

    • AQA's Combined Science Synergy offers a unique thematic approach that helps students make connections between biology, chemistry and physics, which can be more engaging and relevant than traditional separate science courses.
    • The specification is well-supported with a wide range of free resources, including past papers, mark schemes, and practical guides, making it easier for students to revise independently and for teachers to plan effective lessons.
    • AQA is the most popular exam board for GCSE Science in the UK, so there is a wealth of published revision materials, online tutorials and community support available, giving students confidence that help is never far away.

    Frequently Asked Questions

    Specification Topics

    80 topics

    Building blocks

    These are the important building blocks for developing scientific ideas and explanations. The topic moves from particles to atoms to cells, showing the links between the world of ideas and the real world of objects and events. The behaviour of particles in liquids and gases can explain how substances move between cells and through membranes. The topic discusses how cells replicate and how the universal genetic code is a particle pattern. The transfer of energy over small and large distances in living and non-living systems helps us to understand the importance of the way these systems react with each other.

    1 objectives

    States of matter

    The model of particles in motion can be used to account for states of matter, differences in density, the pressure of gases, and changes of state. This model is applied in Transport into and out of cells (page 30) to explain how substances are transported into and out of cells through diffusion and osmosis, and in Systems in the human body (page 36), where it is applied to substances crossing exchange surfaces. The nature of the particles (atoms, molecules and ions) is examined in more detail in Atomic structure (page 24) and Structure and bonding (page 98).

    1 objectives

    A particle model

    Recall and explain the main features of the particle model in terms of the states of matter and change of state, distinguishing between physical and chemical changes., The three states of matter can be represented by a simple model. In this model, particles are represented by small solid spheres. Particle theory can help to explain melting, boiling, freezing and condensing., The three states of matter are solid, liquid and gas. Melting and freezing take place at the melting point, boiling and condensing take place at the boiling point. +2 more

    5 objectives5 subtopics

    Density

    The density of a material is defined by the equation:, density, ρ, in kilograms per metre cubed, kg/m³, Required practical activity 1: use appropriate apparatus to make and record the densities of regular and irregular solid objects and liquids. Volume should be determined from the dimensions of a regularly shaped object and by a displacement technique for irregularly shaped objects. Dimensions to be measured using appropriate apparatus such as a ruler, micrometer or Vernier callipers. +5 more

    8 objectives8 subtopics

    Gas pressure

    The molecules of a gas are in constant random motion. The temperature of the gas is related to the average kinetic energy of the molecules. The higher the temperature, the greater the average kinetic energy and so the faster the average speed of the molecules., Explain how the motion of the molecules in a gas is related both to its temperature and its pressure: hence explain the relation between the temperature of a gas and its pressure at constant volume (qualitative only)., Changing the temperature of a gas, held at constant volume, changes the pressure exerted by the gas. +1 more

    4 objectives4 subtopics

    Heating and changes of state

    E = m L, Describe how heating a system will change the energy stored within the system and raise its temperature or produce changes of state., The specific latent heat of a substance is the amount of energy required to change the state of one kilogram of the substance with no change in temperature. The following equation, given on the Physics equations sheet, applies: +21 more

    24 objectives24 subtopics

    Meanings of purity

    In everyday language, a pure substance can mean a substance that has had nothing added to it, so it is unadulterated and in its natural state., Explain what is meant by the purity of a substance, distinguishing between the scientific and everyday use of the term ‘pure’., Pure elements and compounds melt and boil at specific temperatures. Melting point and boiling point data can be used to distinguish pure substances from mixtures. +1 more

    4 objectives4 subtopics

    Atomic structure

    The study of atomic structure provides a good opportunity to show how scientific methods and theories develop over time. The model introduced in this topic describes atoms in terms of a central nucleus with protons and neutrons surrounded by electrons in a series of energy levels (shells). The ideas in this topic can account for the existence of isotopes and underpin the study of radioactivity (Radiation and risk (page 55)), chemical bonding (Structure and bonding (page 98)) and the periodic table (The periodic table (page 87)).

    1 objectives

    Scientific models of the atom

    Stages in the development of atomic models:, the nuclear atom (1911) – an experiment which showed that most of the alpha particles directed at thin gold foil passed through but a few bounced back, suggesting the positive charge was concentrated at the centre of each gold atom, Plum pudding model (1897) – it was found that the mass of electrons, which had recently been discovered, was very much less than the mass of atoms so they must be sub-atomic particles +4 more

    7 objectives7 subtopics

    The size of atoms

    Atoms are very small, having a radius of about 0.1 nm (1 x 10–¹⁰ m)., Recall the typical size (order of magnitude) of atoms and small molecules., The radius of a small molecule such as methane, CH₄, is about 0.5 nm (5 x 10–¹⁰ m).

    3 objectives3 subtopics

    Sub-atomic particles

    Recall relative charges and approximate relative masses of protons, neutrons and electrons., In an atom, the number of electrons is equal to the number of protons in the nucleus. Atoms have no overall electrical charge., Describe the atom as a positively charged nucleus surrounded by negatively charged electrons, with the nuclear radius much smaller than that of the atom and with almost all of the mass in the nucleus. +4 more

    7 objectives7 subtopics

    Isotopes

    Relate differences between isotopes to differences in conventional representations of their identities, charges and masses., Atoms can be represented as shown in this example:, The sum of the protons and neutrons in an atom is its mass number. +1 more

    4 objectives4 subtopics

    Electrons in atoms

    showing two electrons in the lowest energy level, eight in the second energy level and one in the third energy level., The electrons in an atom occupy the lowest available energy levels (innermost available shells closest to the nucleus). The electronic structure of an atom can be represented by numbers or by a diagram. For example, the electronic structure of sodium is 2,8,1 or, Recall that in each atom its electrons are arranged at different distances from the nucleus.

    3 objectives3 subtopics

    Cells in animals and plants

    Microscopes are used to study cells and so practical work can include the microscopic examination of plant and animal cells., Understanding the structure of cells, the transport of substances into and out of cells, cell division by mitosis and meiosis and cell differentiation lays the foundations for the study of systems in the human body in Systems in the human body (page 36), of plant biology in Plants and photosynthesis (page 42) and of inheritance in Inheritance (page 79).

    2 objectives2 subtopics

    Electron microscopy

    magnification = size of image size of real object, Explain how electron microscopy has increased our understanding of sub- cellular structures., An electron microscope has a much higher resolving power than a light microscope. This means that it can be used to study cells in much finer detail. An electron microscope can magnify up to a million times (× 1000 000) or more, which is much more than a light microscope which has a useful magnification of only about a thousand times (× 1000).

    3 objectives3 subtopics

    Cell structures

    Required practical activity 3: use a light microscope to observe, draw and label a selection of plant and animal cells. A magnification scale must be included., Plant and animal cells (eukaryotic cells) have a cell membrane, cytoplasm and a nucleus containing the genetic material., chloroplasts +12 more

    15 objectives15 subtopics

    Transport into and out of cells

    Active transport allows mineral ions to be absorbed into plant root hairs from very dilute solutions in the soil. It also allows sugar molecules to be absorbed from lower concentrations in the gut into the blood with a higher sugar concentration., the difference in concentration, Some substances move across cell membranes via active transport. Active transport involves the movement of a dissolved substance from a region where it is less concentrated to a region where it is more concentrated. This requires energy from respiration. +7 more

    10 objectives10 subtopics

    Mitosis and the cell cycle

    Dividing cells go through a series of stages called the cell cycle. During the cell cycle the genetic material doubles and then divides to give two new cells that are genetically identical to each other and to the original cell. Knowledge of the stages of the cell cycle and mitosis is not required., Describe the process of mitosis in growth, including the cell cycle., The nucleus of body cells contains chromosomes. In body cells the chromosomes are normally found in pairs. There are 46 chromosomes in human body cells. DNA is in the chromosomes and each chromosome carries a large number of genes. +2 more

    5 objectives5 subtopics

    Meiosis

    When a cell divides to form gametes:, the cell divides twice to form four gametes, each with a single set of chromosomes, Explain the role of meiotic cell division in halving the chromosome number to form gametes. +5 more

    8 objectives8 subtopics

    Cell differentiation

    As an embryo develops most of the cells differentiate and become specialised. Specialised cells carry out a particular function. Differentiation is essential to produce a variety of cells with different functions in multicellular organisms (animals and plants)., Explain the importance of cell differentiation., Cells that have become specialised cannot later change into different kinds of cells. However, there are some stem cells in most adult tissues that are ready to start dividing to replace old cells or to repair damage in the tissues where they are found. +2 more

    5 objectives5 subtopics

    Waves

    the continuous spectrum of electromagnetic waves. The hazards associated with some electromagnetic waves feature in Radiation and risk (page 55)., Water waves and sound waves are used here to distinguish between transverse and longitudinal waves, which transfer energy and information without transferring matter. This leads to the study of

    2 objectives2 subtopics

    Transverse and longitudinal waves

    Describe how ripples on water surfaces are examples of transverse waves whilst sound waves in air are longitudinal waves, and how the speed of each may be measured., In a longitudinal wave the oscillations are parallel to the direction of energy transfer. Longitudinal waves show areas of compression and rarefaction. Sound waves travelling through air are longitudinal., Required practical activity 5: make observations to identify the suitability of apparatus to measure the frequency, wavelength and speed of waves in a ripple tank and waves in a solid and take appropriate measurements. +3 more

    6 objectives6 subtopics

    A wave equation

    period = 1 / frequency, frequency, f, in hertz, Hz, The amplitude of a wave is the maximum displacement of a point on a wave away from its undisturbed position. +13 more

    16 objectives16 subtopics

    Electromagnetic waves

    X-rays – medical imaging and treatments, infrared – electrical heaters, cooking food, infrared cameras, ultraviolet – fluorescent lamps, sun tanning +11 more

    14 objectives14 subtopics

    Radio waves (HT only)

    Recall that radio waves can be produced by, or can themselves induce, oscillations in electrical circuits., When radio waves are absorbed they may create an alternating current with the same frequency as the radio wave itself, so radio waves can themselves induce oscillations in an electrical circuit.

    2 objectives2 subtopics

    Reflection and refraction of electromagnetic waves (HT only)

    Electromagnetic waves change speed when they travel between different substances such as from air to glass or water. As a result they change direction. This is refraction., Recall that different substances may refract, or reflect these waves; explain how some effects are related to differences in the velocity of the waves in different substances., Shiny surfaces act as mirrors when they reflect waves. Rough surfaces scatter waves in all directions.

    3 objectives3 subtopics

    Transport over larger distances

    Larger organisms need systems to transport solids, liquids and gases over larger distances. These systems and processes are monitored and controlled by the human body, but this delicate balance can be disrupted. The topic moves from simple to complex, and outlines the challenges that this presents for any transport system in plants and animals.

    1 objectives

    Systems in the human body

    Systems in the human body can be studied at macroscopic, microscopic and molecular scales. The study of respiration helps to account for the need for exchange surfaces in multicellular organisms, illustrated by the human circulatory system. The study of the digestive system focuses on the chemical changes to the main nutrients in the diet. Finally, examples of the way that body systems are controlled is illustrated with reference to the nervous system and the endocrine system. In Lifestyle and health (page 50) the importance of the endocrine system is further illustrated in the context of lifestyle and health.

    1 objectives

    Respiration

    glucose + oxygen carbon dioxide + water, Organisms need energy for:, Anaerobic respiration in muscles is also exothermic but it gives out less energy. It is represented by the word equation: +11 more

    14 objectives14 subtopics

    Exchange surfaces

    (in animals, for gaseous exchange) being ventilated., having a large surface area, A single-celled organism has a relatively large surface area:volume ratio. +5 more

    8 objectives8 subtopics

    The human circulatory system

    arteries, Gas exchange takes place in the lungs. Important features of the lungs are the trachea, bronchi, alveoli and the capillary network surrounding the alveoli. The alveoli have the specialised surfaces for gas exchange between air and the blood., The heart is a muscular organ that pumps blood around the body in a dual circulatory system. +9 more

    12 objectives12 subtopics

    Blood cells

    platelets., Blood is a tissue consisting of plasma, in which are suspended:, Explain how red blood cells, white blood cells, platelets and plasma are adapted to their functions in the blood. +2 more

    5 objectives5 subtopics

    The human digestive system

    Describe some of the substances transported into and out of a range of organisms in terms of the requirements of those organisms, to include dissolved food molecules and urea., Required practical activity 7: use qualitative reagents to test for a range of carbohydrates, lipids and proteins. To include: Benedict's test for sugars, iodine test for starch and Biuret reagent for protein., Proteins are long-chain molecules made up of many amino acids linked together. Digestion by protease enzymes breaks down proteins to amino acids. Cells use amino acids to make new proteins. +5 more

    8 objectives8 subtopics

    The human nervous system

    Sensory neurones carry impulses from receptors to the spinal cord and brain. Relay neurones carry impulses within the CNS. Motor neurones carry impulses from the CNS to effectors., The nervous system enables humans to react to their surroundings and to coordinate their behaviour., Reflex actions are automatic and rapid; they do not involve the conscious part of the brain. +9 more

    12 objectives12 subtopics

    The human endocrine system

    (HT only) The control of thyroxine levels involves negative feedback. Negative feedback tends to stabilise a system. Any change in the system leads to a response that tends to reverse the change., (HT only) Adrenaline is produced by the adrenal gland. It boosts the delivery of oxygen and glucose to the brain and muscles and prepares the body for ‘flight or fight’., (HT only) Explain the roles of thyroxine and adrenaline in the body including thyroxine as an example of a negative feedback system. +4 more

    7 objectives7 subtopics

    Plants and photosynthesis

    Plants can be attacked by bacteria and viruses so the successful growth of crops depends on methods to prevent or control infection., The study of cells and transport into and out of cells in Cells in animals and plants (page 27) is developed and exemplified here in the context of plant science. A key part is the study of photosynthesis because this underpins work on the carbon cycle and climate change in The Earth's atmosphere (page 67) and the study of ecosystems in Ecosystems and biodiversity (page 75).

    2 objectives2 subtopics

    Meristem tissue

    Describe the function of meristems in plants., Meristem tissue contains the cells in a plant that divide as the plant grows. This type of tissue is found at the growing tips of shoots and roots. The cells differentiate into different types of plant cells depending on where they are in the plant.

    2 objectives2 subtopics

    Plant structures

    Plants take in carbon dioxide from the atmosphere for photosynthesis and oxygen for respiration. Plants take in water from the soil with dissolved ions including nitrate ions to make proteins and magnesium ions to make chlorophyll., Describe some of the substances transported into and out of a range of organisms, in terms of the requirements of those organisms, to include oxygen, carbon dioxide, water and mineral ions., Plants, like other multicellular organisms, need specialised structures for transporting and exchanging materials. The roots, stem and leaves form a plant organ system for transport of substances around the plant.

    3 objectives3 subtopics

    Transpiration

    air movements, which affect the concentration of water vapour in the air around leaves, The rate of transpiration varies with:, Water evaporates in the leaves and the water vapour escapes through tiny holes in the surface of leaves called stomata. The stomata can open or close as conditions change because the guard cells can gain or lose water by osmosis. +9 more

    12 objectives12 subtopics

    Chlorophyll and other plant pigments

    Suggest chromatographic methods for distinguishing pure from impure substances., Different compounds have different R_f values in different solvents, which can be used to help identify the compounds. The compounds in a mixture may separate into different spots depending on the solvent, but a pure compound produces a single spot in all solvents., Rf = distance moved by substance / distance moved by solvent +5 more

    8 objectives8 subtopics

    Photosynthesis

    used to produce amino acids for protein synthesis., Photosynthesis takes place in the chloroplasts in the cells of the leaves of plants. The chloroplasts contain the chlorophyll, which absorbs sunlight., light glucose + oxygen +10 more

    13 objectives13 subtopics

    Factors affecting the rate of photosynthesis

    Explain the effect of temperature, light intensity and carbon dioxide concentration on the rate of photosynthesis., (HT only) Increasing any one of the factors speeds up photosynthesis until the rate is limited by the factor which is in shortest supply., the energy available from light +9 more

    12 objectives12 subtopics

    Translocation

    Phloem tissue is composed of tubes of elongated living cells adapted for translocation of sugars from where they are produced by photosynthesis in the leaves to other parts of the plant for immediate use or storage. Cell sap containing sugars and other nutrients is able to move easily from one phloem cell to the next as the end walls have pores., Explain how the structure of phloem is adapted to its functions in the plant., Describe the process of translocation.

    3 objectives3 subtopics

    Plant diseases

    removing and destroying infected plants, Tobacco mosaic virus is a widespread plant pathogen affecting many species of plants, including tomatoes. It gives a distinctive ‘mosaic’ pattern of discolouration on the leaves, which affects the growth of the plant due to lack of photosynthesis., avoiding wetting the leaves when watering – wet leaves encourage the fungal disease +10 more

    13 objectives13 subtopics

    Interactions with the environment

    This topic looks at the macro- and micro-effects of the interaction between organisms and the environment. It introduces the effects of lifestyle on the delicate balance within the human body. The topic shows how our understanding of electromagnetic waves has developed by investigating how they interact with different materials.

    1 objectives

    Lifestyle and health

    The way in which people live their lives can have long-term consequences for their health. The chances that someone will be affected by conditions such as cardiovascular disease, diabetes or cancer may depend on lifestyle factors, including exercise, diet, alcohol consumption and smoking., Treatments are available to control the symptoms of non-communicable diseases (see also Preventing, treating and curing diseases (page 60)) but the benefits have to be weighed against the risks., The scientific understanding of the reproductive hormones can help people to control their fertility and also to receive treatment for infertility.

    3 objectives3 subtopics

    Health and disease

    Describe different types of diseases (including communicable and non-communicable diseases)., Health can be defined as 'a state of physical, mental and social well-being' and not merely the absence of disease. Factors including diet, stress and life situations can affect both physical and mental health., Diseases stop part of the body from working properly. This causes symptoms, which are experienced by the person affected by the disease. +3 more

    6 objectives6 subtopics

    Risk factors for non-communicable diseases

    Risk factors are aspects of a person’s lifestyle, or substances present in a person’s body or environment, that have been shown to be linked to an increased rate of a disease. For some a causal mechanism has been proven., Explain the effect of lifestyle factors, including exercise, diet, alcohol and smoking, on the incidence of non- communicable diseases at local, national and global levels., the effect of alcohol on liver and brain function +7 more

    10 objectives10 subtopics

    Treatments for cardiovascular disease

    Stents are used to keep the coronary arteries open., In some people heart valves may become faulty, preventing the valve from opening fully, or the heart valve might develop a leak., In coronary heart disease layers of fatty material build up inside the coronary arteries. This reduces the flow of blood through the coronary arteries. This can lead to a heart attack. +4 more

    7 objectives7 subtopics

    Homeostasis

    An organism maintains homeostasis by monitoring its internal conditions and responding appropriately when these conditions deviate from their optimal state., Homeostasis is the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes. Homeostasis is important because it maintains optimal conditions for enzyme action and all cell functions., Control of blood glucose concentration, control of body temperature and control of water levels in the human body are examples of homeostasis. +2 more

    5 objectives5 subtopics

    Insulin and diabetes

    Blood glucose concentration is monitored and controlled by the pancreas., Explain how insulin controls blood sugar levels in the body., (HT only) Explain how glucagon interacts with insulin to control blood sugar levels in the body. +5 more

    8 objectives8 subtopics

    Human reproductive hormones

    Oestrogen and progesterone are involved in maintaining the uterus lining., Describe the roles of hormones in human reproduction, including the menstrual cycle., During puberty reproductive hormones cause secondary sex characteristics to develop. Oestrogen is the main female reproductive hormone produced in the ovary. At puberty eggs begin to mature and one is released approximately every 28 days. This is called ovulation. Testosterone is the main male reproductive hormone produced by the testes and it stimulates sperm production. +4 more

    7 objectives7 subtopics

    Contraception

    Fertility can be controlled by a variety of hormonal and non-hormonal methods of contraception. These include:, barrier methods such as condoms and diaphragms, Explain the use of hormones in contraception and evaluate hormonal and non-hormonal methods of contraception. +6 more

    9 objectives9 subtopics

    Treatments for infertility (HT only)

    giving FSH and LH in a 'fertility drug' to a woman whose own level of FSH is too low, Explain the use of hormones in modern reproductive technologies to treat infertility., The uses of hormones in controlling fertility include: +1 more

    4 objectives4 subtopics

    Radiation and risk

    Ionising radiations include some types of electromagnetic radiation and particles emitted from radioactive atoms. The risks from exposure to ionising radiation can be overestimated in some contexts but underestimated in others. This matters because ionising radiation can damage living, cells in ways that lead to the development of malignant tumours. Understanding of the properties of the different types of ionising radiation helps people to protect themselves and avoid unnecessary exposure to risk.

    2 objectives2 subtopics

    Absorption and emission of radiation

    Recall that the arrangements of electrons in atoms may change with absorption or emission of electromagnetic radiation., When atoms gain energy by heating, from electricity, or by absorbing electromagnetic radiation, some electrons jump to higher energy levels. Electromagnetic radiation is given out when the electrons drop back to lower levels., The frequency of the radiation depends on the size of the energy jump. Atoms of elements such as neon and sodium give out light in the visible region of the spectrum. Other atoms, such as mercury atoms, give out light in the ultraviolet region.

    3 objectives3 subtopics

    Radioactive decay

    an alpha particle (α) – this consists of two neutrons and two protons; it is identical to the nucleus of a helium atom, and a beta particle by the symbol:, Students are not required to recall these two examples. +11 more

    14 objectives14 subtopics

    Half-life

    Radioactive decay is random, so it is not possible to predict which individual nucleus will decay next. But with a large enough number of nuclei it is possible to predict how many will decay in a certain amount of time., The half-life of a radioactive isotope is the average time it takes for the number of nuclei of the isotope in a sample to halve, or the average time it takes for the count rate from a sample containing a radioactive isotope to fall to half its initial level., Explain the concept of half-life and how this is related to the random nature of radioactive decay. +1 more

    4 objectives4 subtopics

    Penetration properties of radiations

    Gamma rays pass through most materials easily but are absorbed by a thick sheet of lead or by several metres of concrete., Recall the differences in the penetration properties of alpha particles, beta particles and gamma rays., Alpha particles are absorbed by just a few millimetres of air or by a thin sheet of paper. +1 more

    4 objectives4 subtopics

    Contamination and irradiation

    Recall the differences between contamination and irradiation effects and compare the hazards associated with these two., Irradiation is the process of exposing an object to radiation from an outside source. Irradiation can be reduced by screening the source or moving the object away from it. The irradiated object does not become radioactive., Radioactive contamination is the unwanted presence of a source of radiation inside, or on the surface of, other materials. It is often difficult to remove the contaminating source so that it continues to add to the radiation dose for as long as it emits radiation.

    3 objectives3 subtopics

    Ionising radiations

    Radiation dose (in Sieverts) is a measure of the risk of harm resulting from an exposure of the body to the radiation. 1 Sievert (Sv) = 1000 millisieverts (mSv)., Recall that changes in atoms and nuclei can also generate and absorb radiations over a wide frequency range., The hazardous effects of ultraviolet (UV) waves, X-rays, alpha, beta and gamma rays depend on the type of radiation and the size of the dose. +3 more

    6 objectives6 subtopics

    Cancer

    Tumours form when cells start growing and dividing in an uncontrolled way. Some tumours are benign; they stay in the same place and stop growing before they get too large., Cancer is caused by malignant tumours that are able to invade neighbouring tissues and spread to different parts of the body in the blood so that more tumours start to grow in other parts of the body., Describe cancer as the result of changes in cells that lead to uncontrolled growth and division.

    3 objectives3 subtopics

    Preventing, treating and curing diseases

    The human body has defence systems to protect it from the pathogens that cause communicable diseases. However, these defences can be breached., The increasing problem of antibiotic resistance (see Evidence for evolution (page 84)) means that research to develop new medicines has to continue. Clinical trials of new drugs have to be carefully planned and the results published so that claims can be subject to peer review and checked by other scientists replicating the investigations., Vaccination helps to protect people from diseases that were once widespread. If the immune system fails, then antibiotics can be used to treat bacterial infections. +1 more

    4 objectives4 subtopics

    Spread of communicable diseases

    through food that is contaminated with bacteria, through the air when people cough or sneeze, through drinking water that is contaminated with microorganisms +4 more

    7 objectives7 subtopics

    Interactions between different types of disease

    immune reactions initially caused by a pathogen can trigger allergies such as skin rashes and asthma, viruses living in cells can be the trigger for cancers, Different types of disease may interact. Some examples include: +3 more

    6 objectives6 subtopics

    Human communicable diseases

    Salmonella food poisoning is spread by bacteria ingested in food, or on food prepared in unhygienic conditions. Fever, abdominal cramps, vomiting and diarrhoea are caused by the bacteria and the toxins they secrete. Salmonella bacteria are killed by cooking and pasteurisation. In the UK, poultry are vaccinated against Salmonella to control the spread., HIV initially causes a 'flu like illness'. Unless successfully treated with antiretroviral drugs the virus attacks the body’s immune cells. Late- stage HIV, or AIDS, occurs when the body’s immune system is no longer able to deal with other infections or cancers. HIV is spread by sexual contact or exchange of body fluids such as blood., Explain how the spread of communicable diseases may be reduced or prevented in animals. This should include a minimum of one common human infection, and sexually transmitted infections in humans including HIV/AIDS. +3 more

    6 objectives6 subtopics

    Defences against pathogens

    the trachea and bronchi secrete mucus that is moved by cilia, The human body defends itself against the entry of pathogens in the following ways:, the nose catches particles +3 more

    6 objectives6 subtopics

    The human immune system

    If a pathogen enters the body the immune system tries to destroy the pathogen. White blood cells are an important part of the immune system. They help to defend against pathogens through:, Explain the role of the immune system of the human body in defence against disease., producing antibodies +2 more

    5 objectives5 subtopics

    Vaccination

    Explain the use of vaccines in the prevention and treatment of disease., Vaccination involves introducing small quantities of dead or inactive forms of a pathogen into the body to stimulate the white blood cells to produce antibodies. If the same pathogen re-enters the body the white blood cells respond quickly to produce antibodies, preventing infection., Students do not need to know details of vaccination schedules and side effects associated with specific vaccines. +1 more

    4 objectives4 subtopics

    Medicines

    Antibiotics, such as penicillin, are medicines that help to cure bacterial disease by killing infective bacteria inside the body. It is important that specific bacteria should be treated by specific antibiotics., The use of antibiotics has greatly reduced deaths from infectious bacterial diseases. However, the emergence of strains of bacteria resistant to antibiotics is becoming a serious threat., Explain that many useful materials are formulations of mixtures. +4 more

    7 objectives7 subtopics

    Testing new drugs

    New drugs are extensively tested for toxicity, efficacy and dose:, Describe the process of discovery and development of potential new medicines, including preclinical and clinical testing., In double-blind trials, some patients are given a placebo. Patients are allocated randomly to groups so that neither the doctors nor the patients know who has received a placebo and who has received the drug until the trial is complete. +3 more

    6 objectives6 subtopics

    Genetic modification

    Explain some of the possible benefits and risks, including practical and ethical considerations, of using gene technology in modern medicine., Research is also exploring the possibility of providing tissues needed for transplants from animals that have been genetically modified so that the tissues are not rejected by the human immune system., New medical products have been produced by genetically modifying bacteria. Insulin for the treatment of Type 1 diabetes is produced by cultivating genetically modified bacteria. +1 more

    4 objectives4 subtopics

    Stem cells

    Type 1 diabetes – using embryo or fetal stem cells., The properties of stem cells are not fully understood. Scientists do not yet know how their differentiation is controlled. This means that there is a fear that their ability to proliferate could lead to cancer when they are transplanted into a patient., Discuss potential benefits and risks associated with the use of stem cells in medicine. +8 more

    11 objectives11 subtopics

    Explaining change

    This topic explores how species, living systems and non-living systems change over time. It explores how scientists think the changes happen in global systems such as Spaceship Earth as well as the tiny changes that happen at a molecular level in the cells of living organisms. The topic discusses how humans affect systems and speculates on how our impact can become benign.

    1 objectives

    The Earth’s atmosphere

    Human activities can also cause pollution on a more local scale, affecting air quality in areas with high traffic levels and contaminating water supplies with sewage., The required practical investigates the use of distillation to purify water., Knowledge of the carbon cycle is crucial to understanding how human activities have changed the atmosphere on a global scale in ways that affect the climate. +3 more

    6 objectives6 subtopics

    Development of the Earth’s atmosphere

    Describe how it is thought an oxygen-rich atmosphere developed over time., Algae and plants produced the oxygen that is now in the atmosphere by photosynthesis., When the oceans formed, carbon dioxide dissolved in the water and carbonates were precipitated producing sediments, reducing the amount of carbon dioxide in the atmosphere. +5 more

    8 objectives8 subtopics

    The carbon cycle

    Describe photosynthetic organisms as the main producers of food and therefore biomass for life on Earth., The element carbon is found as carbon dioxide in the atmosphere, dissolved in the water of the oceans, as calcium carbonate in sea shells, in fossil fuels and in limestone rocks, and as carbohydrates and other large molecules in all living organisms. Carbon cycles through the environment by processes that include photosynthesis, respiration, combustion of fuels and the industrial uses of limestone., Explain the importance of the carbon cycle to living organisms. +4 more

    7 objectives7 subtopics

    The greenhouse effect

    Greenhouse gases in the atmosphere maintain temperatures on Earth high enough to support life. They allow short-wavelength radiation from the Sun to pass through the atmosphere to the Earth’s surface but absorb the outgoing long- wavelength radiation from the Earth’s surface, causing an increase in temperature. Water vapour, carbon dioxide and methane are greenhouse gases that increase the absorption of outgoing, long-wavelength radiation., (HT only) Recall that different substances may absorb, transmit or reflect these waves in ways that vary with wavelength., Describe the greenhouse effect in terms of the interaction of radiation with matter.

    3 objectives3 subtopics

    Human impacts on the climate

    Scientists analyse data on climate change using computer models based on the physics that describes the movements of mass and energy in the climate system. Many complex changes on Earth affect the climate, and detailed data about the scale of the changes is not available from all over the world. Also, when predicting climate change, scientists have to make assumptions about future greenhouse gas emissions. This means that there are uncertainties in the predictions., Evaluate the evidence for additional anthropogenic causes of climate change, including the correlation between change in atmospheric carbon dioxide concentration and the consumption of fossil fuels, and describe the uncertainties in the evidence base., Climate describes the long-term patterns of weather in different parts of the world. Climate change is shown by changes to patterns in measures of such things as air temperature, rainfall, sunshine and wind speed. +1 more

    4 objectives4 subtopics

    Climate change: impacts and mitigation

    using energy resources more efficiently, Steps can be taken to mitigate the effects of climate change by reducing the overall rate at which greenhouse gases are added to the atmosphere. Examples of mitigation include:, reducing waste by recycling +4 more

    7 objectives7 subtopics

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