The AQA GCSE Combined Science: Trilogy (Biology) Syllabus

If you’re preparing for the GCSE Combined Science: Trilogy exam, the first step is to be aware of what topics make up the syllabus. In this blog post, we state the topics students are expected to know ahead of the exam, explaining what students need to know.

There are seven topics covered by the GCSE Combined Science: Trilogy (Biology) syllabus, split across two test papers:

Cell Biology
Organisation
Infection and Response
Bioenergetics
Homeostasis and Response
Inheritance, Variation and Evolution
Ecology

The information below highlights what students should prepare for ahead of the GCSE combined science exam. For further information on the syllabus subjects, please visit the AQA website.

Cell Biology

Cell structure

Eukaryotes and prokaryotes

Students should be able to:

demonstrate an understanding of the scale and size of cells and be able to make order of magnitude calculation
use estimations and explain when they should be used to judge the relative size or area of sub-cellular structures
recognise, draw and interpret images of cells

Cell specialisation and differentiation

Students should be able to:

explain the importance of cell differentiation
when provided with appropriate information, explain how the structure of different types of cell relate to their function in a tissue, an organ or organ system, or the whole organism

Microscopy

Students should be able to:

understand how microscopy techniques have developed over time and explain how electron microscopy has increased understanding of subcellular structures
carry out calculations involving magnification, real size and image size using the formula:

Cell Division

Chromosomes

Mitosis & the cell cycle

Students need to:

understand the three overall stages of the cell cycle but do not need to know the different phases of the mitosis stage. They should also be able to recognise and describe situations in given contexts where mitosis is occurring

Students should be able to:

recognise and describe situations in given contexts where mitosis is occurring

Stem cells

Students should be able to:

describe the function of stem cells in embryos, in adult animals and in the meristems in plants
evaluate the practical risks and benefits, as well as social and ethical issues, of the use of stem cells in medical research and treatments.

Transport in Cells

Diffusion

Students should be able to:

explain how different factors affect the rate of diffusion
calculate and compare surface area to volume ratios
explain the need for exchange surfaces and a transport system in multicellular organisms in terms of surface area to volume ratio
explain how the small intestine and lungs in mammals, gills in fish, and the roots and leaves in plants, are adapted for exchanging materials

Osmosis

Students should be able to:

use simple compound measures of rate of water uptake
use percentages
calculate percentage gain and loss of mass of plant tissue
plot, draw and interpret appropriate graphs.

Active transport

Students should be able to:

describe how substances are transported into and out of cells by diffusion, osmosis and active transport
explain the differences between the three processes

Organisation

Principles of organisation

Students should be able to:

develop an understanding of size and scale in relation to cells, tissues, organs and systems.

Animal tissues, organs and organ systems

The human digestive system

Students should be able to:

relate knowledge of enzymes to metabolism
describe the nature of enzyme molecules and relate their activity to temperature and pH changes
carry out rate calculations for chemical reactions
use the ‘lock and key theory’ as a simplified model to explain enzyme action
recall the sites of production and the action of amylase, proteases and lipases
understand simple word equations but no chemical symbol equations are required
use other models to explain enzyme action.The heart and blood vessels

The heart and blood vessels

Students should be able to:

now the structure and functioning of the human heart and lungs, including how lungs are adapted for gaseous exchange
explain how the structure of these vessels relates to their functions
use simple compound measures such as rate and carry out rate calculations for blood flow
recognise different types of blood cells in a photograph or diagram, and explain how they are adapted to their functions

Blood

Students should:

know the functions of each of these blood components
evaluate risks related to use of blood products

Coronary heart disease: a non-communicable disease

Students should be able to:

evaluate the advantages and disadvantages of treating cardiovascular diseases by drugs, mechanical devices or transplant
evaluate methods of treatment bearing in mind the benefits and risks associated with the treatment.

Health issues

Students should be able to:

describe the relationship between health and disease and the interactions between different types of disease
translate disease incidence information between graphical and numerical forms, construct and interpret frequency tables and diagrams, bar charts and histograms, and use a scatter diagram to identify a correlation between two variables
understand the principles of sampling as applied to scientific data, including epidemiological data.

The effect of lifestyle on some non-communicable diseases

Students should be able to:

discuss the human and financial cost of these non-communicable diseases to an individual, a local community, a nation or globally
explain the effect of lifestyle factors including diet, alcohol and smoking on the incidence of non-communicable diseases at local, national and global levels.
understand the principles of sampling as applied to scientific data in terms of risk factors
translate information between graphical and numerical forms; and extract and interpret information from charts, graphs and tables in terms of risk factors
use a scatter diagram to identify a correlation between two variables in terms of risk factors

Cancer

Students should be able to:

describe cancer as the result of changes in cells that lead to uncontrolled growth and division.

Plant tissues and organ system of plants

Plant tissues

Students should be able to:

explain how the structures of plant tissues are related to their functions
explain how the structure of root hair cells, xylem and phloem are adapted to their functions
understand and use simple compound measures such as the rate of transpiration

Plant organ system

Students should be able to:

explain how the structure of root hair cells, xylem and phloem are adapted to their functions
explain the effect of changing temperature, humidity, air movement and light intensity on the rate of transpiration
measure the rate of transpiration by the uptake of water
investigate the distribution of stomata and guard cells
process data from investigations involving stomata and transpiration rates to find arithmetic means, understand the principles of sampling and calculate surface areas and volumes
understand and use simple compound measures such as the rate of transpiration
translate information between graphical and numerical form plot and draw appropriate graphs, selecting appropriate scales for axes
extract and interpret information from graphs, charts and tables
describe the process of transpiration and translocation, including the structure and function of the stomata

Infection and Response

Communicable diseases

Communicable (infectious) diseases

Students should be able to:

explain how diseases caused by viruses, bacteria, protists and fungi are spread in animals and plants
explain how the spread of diseases can be reduced or prevented

Viral disease

Bacterial diseases

Fungal diseases

Protist diseases

Human defence systems

Students should be able to:

describe the non-specific defence systems of the human body against pathogens, including the:
- skin
- Nose
- trachea and bronchi
- stomach
explain the role of the immune system in the defence against disease

Vaccination

Students should be able to:

explain how vaccination will prevent illness in an individual, and how the spread of pathogens can be reduced by immunising a large proportion of the population.

Students do not need to know details of vaccination schedules and side effects associated with specific vaccines

Antibiotics and painkillers

Students should be able to:

explain the use of antibiotics and other medicines in treating disease

Discovery and development of drugs

Students should be able to:

describe the process of discovery and development of potential new medicines, including preclinical and clinical testing.

Bioenergetics

Photosynthesis

Photosynthesis reaction

Students should be able to:

describe photosynthesis as an endothermic reaction in which energy is transferred from the environment to the chloroplasts by light
explain the effects of temperature, light intensity, carbon dioxide concentration, and the amount of chlorophyll on the rate of photosynthesis

Rate of photosynthesis

Students should be able to:

explain the effects of temperature, light intensity, carbon dioxide concentration, and the amount of chlorophyll on the rate of photosynthesis
measure and calculate rates of photosynthesis
extract and interpret graphs of photosynthesis rate involving one limiting factor
plot and draw appropriate graphs selecting appropriate scale for axes
translate information between graphical and numeric form
(Higher Tier only) explain graphs of photosynthesis rate involving two or three factors and decide which is the limiting factor
(Higher Tier only) understand and use inverse proportion – the inverse square law and light intensity in the context of photosynthesis.

Uses of glucose from photosynthesis

Respiration

Aerobic and anaerobic respiration

Students should be able to:

describe cellular respiration as an exothermic reaction which is continuously occurring in living cells
compare the processes of aerobic and anaerobic respiration with regard to the need for oxygen, the differing products and the relative amounts of energy transferred

Response to exercise

Students should be able to:

describe how the human body reacts to the increased demand for energy when exercising, such as heart rate, breathing rate and breathing volume.

Metabolism

Students should be able to:

explain the importance of sugars, amino acids, fatty acids and glycerol in the synthesis and breakdown of carbohydrates, proteins and lipids.

Homeostasis and Response

Homeostasis

Students should be able to:

explain that 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.

The human nervous system

Students should be able to:

explain how the structure of the nervous system is adapted to its functions
explain how the various structures in a reflex arc – including the sensory neurone, synapse, relay neurone and motor neurone – relate to their function
extract and interpret data from graphs, charts and tables, about the functioning of the nervous system
translate information about reaction times between numerical and graphical forms.

Hormonal coordination in humans

Human endocrine system

Students must be able to:

describe the principles of hormonal coordination and control by the human endocrine system.

Students should be able to:

identify the position of the following on a diagram of the human body:
- pituitary gland
- pancreas
- thyroid
- adrenal gland
- ovary
- testes

Control of blood glucose concentration

Students should be able to:

explain how insulin controls blood glucose (sugar) levels in the body
compare Type 1 and Type 2 diabetes and explain how they can be treated
extract information and interpret data from graphs that show the effect of insulin in blood glucose levels in both people with diabetes and people without diabetes.
(Higher Tier Only) explain how glucagon interacts with insulin in a negative feedback cycle to control blood glucose (sugar) levels in the body.

Hormones in human reproduction

Students should be able to:

describe the roles of hormones in human reproduction, including the menstrual cycle.
(Higher Tier Only) explain the interactions of FSH, oestrogen, LH and progesterone, in the control of the menstrual cycle
(Higher Tier Only) extract and interpret data from graphs showing hormone levels during the menstrual cycle

Contraception

Students should be able to:

evaluate the different hormonal and non-hormonal methods of contraception.

Infertility (Higher Tier Only)

Students should be able to:

explain the use of hormones in modern reproductive technologies to treat infertility.

Feedback systems (Higher Tier Only)

Students should be able to:

explain the roles of thyroxine and adrenaline in the body.

Inheritance, Variation and Evolution

Reproduction

Sexual and asexual reproduction

Students should:

understand that meiosis leads to non-identical cells being formed while mitosis leads to identical cells being formed

Meiosis

Students should be able to:

explain how meiosis halves the number of chromosomes in gametes and fertilisation restores the full number of chromosomes

DNA and genome definition

Students should be able to:

describe the structure of DNA and define genome
discuss the importance of understanding the human genome.

Genetic inheritance

Students should be able to:

understand the concept of probability in predicting the results of a single gene cross, but recall that most phenotype features are the result of multiple genes rather than single gene inheritance
use direct proportion and simple ratios to express the outcome of a genetic cross
complete a Punnett square diagram and extract and interpret information from genetic crosses and family trees
(Higher Tier only) construct a genetic cross by Punnett square diagram and use it to make predictions using the theory of probability

Inherited disorders

Students should:

make informed judgements about the economic, social and ethical issues concerning embryo screening, given appropriate information.

Sex determination

Students should be able to:

carry out a genetic cross to show sex inheritance and understand and use direct proportion and simple ratios in genetic crosses.

Students should:

understand and use direct proportion and simple ratios in genetic crosses.

Variation and evolution

Students should be able to:

describe simply how the genome and its interaction with the environment influence the development of the phenotype of an organism
describe evolution as a change in the inherited characteristics of a population over time through a process of natural selection which may result in the formation of a new species

Evolution

Students should be able to:

describe evolution as a change in the inherited characteristics of a population over time through a process of natural selection which may result in the formation of a new species
explain how evolution occurs through natural selection of variants that give rise to phenotypes best suited to their environment.

Selective breeding

Students should be able to:

explain the impact of selective breeding of food plants and domesticated animals.

Genetic engineering

Students should be able to:

describe genetic engineering as a process which involves modifying the genome of an organism by introducing a gene from another organism to give a desired characteristic
explain the potential benefits and risks of genetic engineering in agriculture and in medicine and that some people have objections
(Higher Tier only) describe the main steps in the process of genetic engineering.

Evidence for evolution

Students should be able to:

describe the evidence for evolution including fossils and antibiotic resistance in bacteria.

Fossils

Students should be able to:

extract and interpret information from charts, graphs and tables such as evolutionary tree.

Extinction

Students should be able to:

describe factors which may contribute to the extinction of a species

Resistant bacteria

Classification of living organisms

Students should be able to:

use information given to show understanding of the Linnaean system
describe the impact of developments in biology on classification systems.

Ecology

Communities

Students should be able to describe:

different levels of organisation in an ecosystem from individual organisms to the whole ecosystem
the importance of interdependence and competition in a community
extract and interpret information from charts, graphs and tables relating to the interaction of organisms within a community

Students should be able to, when provided with appropriate information:

suggest the factors for which organisms are competing in a given habitat
suggest how organisms are adapted to the conditions in which they live.

Abiotic factors

Students should be able to:

explain how a change in an abiotic factor would affect a given community given appropriate data or context.

Biotic factors

Students should be able to:

explain how a change in a biotic factor might affect a given community given appropriate data or context
extract and interpret information from charts, graphs and tables relating to the effect of biotic factors on organisms within a community

Adaptations

Students should be able to:

explain how organisms are adapted to live in their natural environment, given appropriate information

Organisation of an ecosystem

Levels of organisation

Students should understand that photosynthetic organisms are the producers of biomass for life on Earth.

Students should be able to:

interpret graphs used to model these cycles

How materials are cycled

Students should be able to:

recall that many different materials cycle through the abiotic and biotic components of an ecosystem
explain the importance of the carbon and water cycles to living organisms
explain the role of microorganisms in cycling materials through an ecosystem by returning carbon to the atmosphere as carbon dioxide and mineral ions to the soil

Students are not expected to study the nitrogen cycle

Biodiversity and the effect of human interaction on ecosystems

Biodiversity

Students should be able to:

explain how waste, deforestation and global warming have an impact on biodiversity.

Waste management

Students should:

understand that rapid growth in the human population and an increase in the standard of living mean that increasingly more resources are used and more waste is produced.

Land use

Students should:

understand the conflict between the need for cheap available compost to increase food production and the need to conserve peat bogs and peatlands as habitats for biodiversity and to reduce carbon dioxide emissions.

Deforestation

Students should be able to:

evaluate the environmental implications of deforestation.

Global warming

Students should be able to:

describe some of the biological consequences of global warming

Maintaining biodiversity

Students should be able to:

describe both positive and negative human interactions in an ecosystem and explain their impact on biodiversity
evaluate given information about methods that can be used to tackle problems caused by human impacts
on the environment
explain and evaluate the conflicting pressures on maintaining biodiversity given appropriate information

At GCSEScience.UK, we provide membership giving you access to a course covering the whole syllabus that will enable you to pass your exam with flying colours as well as exam questions to help boost your confidence and enable you to perform at your best on exam day. Additionally, membership gives you access to our study groups and forums, allowing you to interact with other GCSE Science students.

Our AQA GCSE Combined Science (Trilogy) syllabus covers all seven topics in biology, seven topics in chemistry and ten topics in physics.