Science 0654 (2025-): Biology

Characteristics of living organisms

Cells

Movement into and out of cells

Biological molecules

Enzymes

Plant nutrition

Human nutrition

Transport in plants

Transport in animals

Diseases and immunity

Gas exchange in humans

Respiration

Coordination and response

Drugs

Reproduction

Inheritance

Variation and selection

Organisms and their environment

Human influences on ecosystems

Characteristics of living organisms

Cell structure

Size of specimen

Diffusion

Osmosis

Active transport

Biological molecules

Enzymes

Photosynthesis

Leaf structure

Diet

Digestive system

Digestion

Xylem and phloem

Water uptake

Transpiration

Translocation

Circulatory systems

Heart

Blood vessels

Blood

Diseases and immunity

Gas exchange in humans

Respiration

Coordination and response

Hormones

Homeostasis

Drugs

Asexual reproduction

Sexual reproduction

Sexual reproduction in plants

Sexual reproduction in humans

Sexually transmitted infections

Chromosomes and genes

Cell division

Monohybrid inheritance

Variation

Selection

Energy flow

Food chains and food webs

Carbon cycle

Habitat destruction

Conservation

Describe the characteristics of living organisms by defining

Describe and compare the structure of a plant cell with an animal cell, limited to cell wall, cell membrane, nucleus, cytoplasm, chloroplasts, ribosomes, mitochondria, vacuoles

Describe the structure of a bacterial cell, limited to cell wall, cell membrane, cytoplasm, ribosomes, circular DNA, plasmids

Identify the cell structures listed in 2.1.1 and 2.1.2 in diagrams and images of plant, animal and bacterial cells

Describe the functions of the structures listed in 2.1.1 and 2.1.2 in plant, animal and bacterial cells

State that new cells are produced by division of existing cells

State that specialised cells have specific functions, limited to

State and use the formula magnification = image size / actual size

Calculate magnification and size of biological specimens using millimetres as units

Convert measurements between millimetres(mm) and micrometres (μm)

Describe diffusion as the net movement of particles from a region of their higher concentration to a region of their lower concentration (i.e. down a concentration gradient), as a result of their random movement

State that some substances move into and out of cells by diffusion through the cell membrane

Describe the importance of diffusion of gases and solutes in living organisms

Investigate the factors that influence diffusion, limited to surface area, temperature, concentration gradient and distance

State that water diffuses through partially permeable membranes by osmosis

State that water moves into and out of cells by osmosis through the cell membrane 

Investigate and describe the effects on plant tissues of immersing them in solutions of different concentrations

Describe osmosis as the net movement of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution), through a partially permeable membrane

Explain the effects on plant cells of immersing them in solutions of different concentrations by using the terms turgid, turgor pressure, plasmolysis, flaccid 

Explain the importance of water potential and osmosis in the uptake and loss of water by organisms

Describe active transport as the movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration (i.e. against a concentration gradient), using energy from respiration

Explain the importance of active transport as a process for movement of molecules or ions across membranes, including ion uptake by root hairs

List the chemical elements that make up carbohydrates, fats and proteins 

State that large molecules are made from smaller molecules, limited to

Describe the use of

Describe enzymes as proteins that are involved in all metabolic reactions, where they function as biological catalysts

Investigate and describe the effect of changes in temperature and pH on enzyme activity

Describe and explain enzyme action with reference to the active site, enzyme-substrate complex, substrate and product 

Describe and explain the specificity of enzymes in terms of the complementary shape and fit of the active site with the substrate

Explain the effect of changes in temperature on enzyme activity in terms of kinetic energy, shape and fit, frequency of effective collisions and denaturation

Explain the effect of changes in pH on enzyme activity in terms of shape and fit and denaturation

Describe photosynthesis as the process by which plants synthesise carbohydrates from raw materials using energy from light

tate the word equation for photosynthesis as carbon dioxide + water → glucose + oxygen (in the presence of light and chlorophyll)

State that chlorophyll is a green pigment that is found in chloroplasts

Investigate and understand the need for chlorophyll, light and carbon dioxide for photosynthesis

State the balanced symbol equation for photosynthesis as 6CO2 + 6H2O → C6H12O6 + 6O2

State that chlorophyll transfers energy from light into energy in chemicals, for the synthesis of carbohydrates 

Outline the subsequent use and storage of the carbohydrates made in photosynthesis

Explain the importance of

Understand and describe the effects of varying light intensity, carbon dioxide concentration and temperature on the rate of photosynthesis

Understand and describe the effect of light and dark conditions on gas exchange in an aquatic plant using hydrogencarbonate indicator solution

State that most leaves have a large surface area and are thin, and explain how these features are adaptations for photosynthesis 

Identify in diagrams and images the following structures in the leaf of a dicotyledonous plant chloroplasts, cuticle, guard cells and stomata, upper and lower epidermis, palisade mesophyll, spongy mesophyll, air spaces, vascular bundles, xylem and phloem

Explain how the structures listed in B6.2.2 adapt leaves for photosynthesis

Describe what is meant by a balanced diet 

State the principal dietary sources and describe the importance of

State the causes of scurvy and rickets

Identify in diagrams and images the main organs of the digestive system, limited to

Describe the functions of the organs of the digestive system listed in B7.2.1, in relation to

Describe physical digestion as the breakdown of food into smaller pieces without chemical change to the food molecules 

State that physical digestion increases the surface area of food for the action of enzymes in chemical digestion

Describe chemical digestion as the breakdown of large insoluble molecules into small soluble molecules

State the role of chemical digestion in producing small soluble molecules that can be absorbed

Describe the functions of enzymes as follows

State where, in the digestive system, amylase, protease and lipase are secreted and where they act 

Describe the functions of hydrochloric acid in gastric juice, limited to killing harmful microorganisms in food and providing an acidic pH for optimum enzyme activity of proteases in the stomach

Explain that bile is an alkaline mixture that neutralises the acidic mixture of food and gastric juices entering the duodenum from the stomach, to provide a suitable pH for enzyme action in the small intestine

Outline the role of bile in emulsifying fats and Oils to increase the surface area for chemical digestion

State the functions of xylem and phloem 

Identify in diagrams and images the position of xylem and phloem as seen in sections of roots, stems and leaves of non-woody dicotyledonous plants

Identify in diagrams and images root hair cells and state their functions

State that the large surface area of root hairs increases the uptake of water and mineral ions

Outline the pathway taken by water through root, stem and leaf as root hair cells, root cortex cells, xylem, mesophyll cells

Describe transpiration as the loss of water vapour from leaves 

State that water evaporates from the surfaces of the mesophyll cells into the air spaces and then diffuses out of the leaves through the stomata as water vapour

Investigate and describe the effects of variation of temperature and wind speed on transpiration rate

Explain the effects on the rate of transpiration of varying the following temperature, wind speed and humidity

Explain how and why wilting occurs

Describe translocation as the movement of sucrose and amino acids in phloem from sources to sinks

Describe

Describe the circulatory system as a system of blood vessels with a pump and valves to ensure one-way flow of blood

Describe the single circulation of a fish

Describe the double circulation of a mammal

Explain the advantages of a double circulation

Identify in diagrams and images the structures of the mammalian heart, limited to: muscular wall, septum, left and right ventricles, left and right atria, one-way valves and coronary arteries

State that blood is pumped away from the heart in arteries and returns to the heart in veins

State that the activity of the heart may be monitored by: ECG (electrocardiogram), pulse rate and listening to sounds of valves closing 

Investigate and describe the effect of physical activity on the heart rate 

Describe coronary heart disease in terms of the blockage of coronary arteries and state the possible risk factors including: diet, lack of exercise, stress, smoking, genetic predisposition, age and sex 

Discuss the roles of diet and exercise in reducing the risk of coronary heart disease

Describe the functioning of the heart in terms of the contraction of muscles of the atria and ventricles and the action of the valves

Explain the effect of physical activity on the heart rate

Describe the structure of arteries, veins and capillaries, limited to: relative thickness of wall, diameter of the lumen and the presence of valves in veins

State the functions of capillaries

Explain how the structure of arteries and veins is related to the pressure of the blood that they transport

Explain how the structure of capillaries is related to their functions

Identify in diagrams and images the main blood vessels to and from the:

List the components of blood as: red blood cells, white blood cells, platelets and plasma 

Identify red and white blood cells in photomicrographs and diagrams

State the functions of the following components of blood:

Identify lymphocytes and phagocytes in photomicrographs and diagrams 

State the functions of: 

State the roles of blood clotting as preventing blood loss and the entry of pathogens

Describe a pathogen as a disease-causing organism

State that a pathogen is transmitted:

Describe a transmissible disease as a disease in which the pathogen can be passed from one host to another

Describe the body defences against pathogens, limited to: skin, hairs in the nose, mucus, stomach acid and white blood cells 

Explain the importance of the following in controlling the spread of disease:

State that vaccinations are available for some pathogens to help control the spread of diseases

State the features of viruses, limited to a protein coat and genetic material

Describe active immunity as defence against a pathogen by antibody production in the body

State that each pathogen has its own antigens, which have specific shapes 

Describe antibodies as proteins that bind to antigens leading to direct destruction of pathogens or marking of pathogens for destruction by phagocytes 

State that specific antibodies have complementary shapes which fit specific antigens

Explain that active immunity is gained after an infection by a pathogen or by vaccination 

Outline the process of vaccination:

Explain the role of vaccination in controlling the spread of diseases

Identify in diagrams and images the following parts of the breathing system: lungs, diaphragm, ribs, intercostal muscles, larynx, trachea, bronchi, bronchioles, alveoli and associated capillaries

Investigate the differences in composition between inspired and expired air using limewater as a test for carbon dioxide

Describe the differences in composition between inspired and expired air, limited to: oxygen, carbon dioxide and water vapour

Investigate and describe the effects of physical activity on the rate and depth of breathing

Describe the features of gas exchange surfaces in humans, limited to: large surface area, thin surface, good blood supply and good ventilation with air

Explain the differences in composition between inspired and expired air

Explain the link between physical activity and the rate and depth of breathing in terms of: an increased carbon dioxide concentration in the blood, which is detected by the brain, leading to an increased rate and greater depth of breathing

State the uses of energy in living organisms, including: muscle contraction, protein synthesis, cell division, growth, the passage of nerve impulses and the maintenance of a constant body temperature

Describe aerobic respiration as the chemical reactions in cells that use oxygen to break down nutrient molecules to release energy

State the word equation for aerobic respiration as: glucose + oxygen → carbon dioxide + water

State the balanced symbol equation for aerobic respiration as: C6H12O6 + 6O2 → 6CO2 + 6H2O

Describe anaerobic respiration as the chemical reactions in cells that break down nutrient molecules to release energy without using oxygen

State that anaerobic respiration releases much less energy per glucose molecule than aerobic respiration

State the word equation for anaerobic respiration in muscles during vigorous exercise as: glucose → lactic acid

State that lactic acid builds up in muscles and blood during vigorous exercise causing an oxygen debt 

Outline how the oxygen debt is removed after exercise, limited to:

State that electrical impulses travel along neurones

Describe the mammalian nervous system in terms of:

Describe the role of the nervous system as coordination and regulation of body functions 

Identify in diagrams and images sensory, relay and motor neurones 

Describe a simple reflex arc in terms of: receptor, sensory neurone, relay neurone, motor neurone and effector

Describe a reflex action as a means of automatically and rapidly integrating and coordinating stimuli with the responses of effectors (muscles and glands) 

Describe sense organs as groups of receptor cells responding to specific stimuli: light, sound, touch, temperature and chemicals

Describe a hormone as a chemical substance, produced by a gland and carried by the blood, which alters the activity of one or more specific target organs

Identify in diagrams and images specific endocrine glands and state the hormones they secrete, limited to:

Describe adrenaline as the hormone secreted in 'fight or flight' situations and its effects, limited to:

State that glucagon is secreted by the pancreas

Describe homeostasis as the maintenance of a constant internal environment

Explain the concept of homeostatic control by negative feedback with reference to a set point 

Describe the control of blood glucose concentration by the liver and the roles of insulin and glucagon 

Identify in diagrams and images of the skin: hairs, hair erector muscles, sweat glands, receptors, sensory neurones, blood vessels and fatty tissue 

Describe the maintenance of a constant Internal body temperature in mammals in terms of:

Describe a drug as any substance taken into the body that modifies or affects chemical reactions in the body

Describe the use of antibiotics for the treatment of bacterial infections

State that some bacteria are resistant to antibiotics which reduces the effectiveness of antibiotics

State that antibiotics kill bacteria but do not affect viruses

Explain how using antibiotics only when essential can limit the development of resistant bacteria such as MRSA

Describe asexual reproduction as a process resulting in the production of genetically identical offspring from one parent 

Identify examples of asexual reproduction in diagrams, images and information provided

Discuss the advantages and disadvantages of asexual reproduction to a population of a species in the wild

Describe sexual reproduction as a process involving the fusion of the nuclei of two gametes to form a zygote and the production of offspring that are genetically different from each other

Describe a species as a group of organisms that can reproduce to produce fertile offspring

State that nuclei of gametes are haploid and that the nucleus of a zygote is diploid

Discuss the advantages and disadvantages of sexual reproduction to a population of a species in the wild

Identify in diagrams and images and draw the following parts of an insect-pollinated flower: sepals, petals, stamens, filaments, anthers, carpels, style, stigma, ovary and ovules 

State the functions of the structures listed in B15.3.1

Describe pollination as the transfer of pollen grains from an anther to a stigma

State that fertilisation occurs when a pollen nucleus fuses with a nucleus in an ovule

Describe the structural adaptations of insectpollinated and wind-pollinated flowers 

Investigate and describe the environmental conditions that affect germination of seeds, limited to the requirement for: water, oxygen and a suitable temperature

Identify in diagrams and images and describe the anthers and stigmas of a wind-pollinated flower

Identify on diagrams and state the functions of the following parts of the male reproductive system: testes, scrotum, sperm ducts, prostate gland, urethra and penis 

Identify on diagrams and state the functions of the following parts of the female reproductive system: ovaries, oviducts, uterus, cervix and vagina

Describe fertilisation as the fusion of the nuclei from a male gamete (sperm) and a female gamete (egg cell)

Describe the roles of testosterone and oestrogen in the development and regulation of secondary sexual characteristics during puberty

Describe the menstrual cycle in terms of changes in the ovaries and in the lining of the uterus knowledge of sex hormones is not required)

Explain the adaptive features of sperm, limited to: flagellum, mitochondria and the presence of enzymes in the acrosome 

Explain the adaptive features of egg cells, limited to: energy stores and the jelly coat that changes at fertilisation

Compare male and female gametes in terms of: size, structure, motility and numbers

Describe a sexually transmitted infection (STI) as an infection that is transmitted through sexual contact

State that human immunodeficiency virus (HIV) is a pathogen that causes an STI

State that HIV infection may lead to AIDS 

Describe the methods of transmission of HIV 

Explain how the spread of STIs is controlled

State that chromosomes are made of DNA, which contains genetic information in the form of genes 

Define a gene as a length of DNA that codes for a protein

Define an allele as an alternative form of a gene

Describe the inheritance of sex in humans with reference to XX and XY chromosomes

Describe a haploid nucleus as a nucleus containing a single set of chromosomes

Describe a diploid nucleus as a nucleus containing two sets of chromosomes

State that in a diploid cell, there is a pair of each type of chromosome and in a human diploid cell there are 23 pairs

Describe mitosis as nuclear division giving rise to genetically identical cells (details of the stages of mitosis are not required)

State the role of mitosis in growth, repair of damaged tissues, replacement of cells and asexual reproduction

State that the exact replication of chromosomes occurs before mitosis

State that during mitosis, the copies of chromosomes separate, maintaining the chromosome number in each daughter cell

State that meiosis is involved in the production of gametes

Describe meiosis as reduction division in which the chromosome number is halved from diploid to haploid resulting in genetically different cells (details of the stages of meiosis are not required)

Describe inheritance as the transmission of genetic information from generation to generation 

Describe genotype as the genetic make-up of an organism and in terms of the alleles present

Describe phenotype as the observable features of an organism 

Describe homozygous as having two identical alleles of a particular gene 

State that two identical homozygous individuals that breed together will be purebreeding 

Describe heterozygous as having two different alleles of a particular gene 

State that a heterozygous individual will not be pure-breeding

Describe a dominant allele as an allele that is expressed if it is present in the genotype 

Describe a recessive allele as an allele that is only expressed when there is no dominant allele of the gene present in the genotype

Interpret pedigree diagrams for the inheritance of a given characteristic 

Use genetic diagrams to predict the results of monohybrid crosses and calculate phenotypic ratios, limited to 1:1 and 3:1 ratios

Use Punnett squares in crosses which result in more than one genotype to work out and show the possible different genotypes

Describe variation as differences between individuals of the same species

State that continuous variation results in a range of phenotypes between two extremes; examples include body length

State that discontinuous variation results in a limited number of phenotypes with no intermediates; examples include ABO blood groups

Describe mutation as a genetic change 

Describe natural selection with reference to:

Describe selective breeding with reference to: 

Outline how selective breeding by artificial selection is carried out over many generations to improve crop plants and domesticated animals and apply this to given contexts

Describe the development of strains of antibiotic-resistant bacteria as an example of natural selection

State that the Sun is the principal source of energy input to biological systems

Describe the flow of energy through living organisms, including light energy from the Sun and chemical energy in organisms, and its eventual transfer to the environment

Describe a food chain as showing the transfer of energy from one organism to the next, beginning with a producer 

Construct and interpret simple food chains

Describe a food web as a network of interconnected food chains and interpret food webs

Describe a producer as an organism that makes its own organic nutrients, usually using energy from sunlight, through photosynthesis

Describe a consumer as an organism that gets its energy by feeding on other organisms 

State that consumers may be classed as primary, secondary and tertiary according to their position in a food chain 

Describe a herbivore as an animal that gets its energy by eating plants 

Describe a carnivore as an animal that gets its energy by eating other animals 

Describe a decomposer as an organism that gets its energy from dead or waste organic material 

Use food chains and food webs to describe the impact humans have through overharvesting of food species and through introducing foreign species to a habitat

Describe a trophic level as the position of an organism in a food chain and food web 

Identify the following as the trophic levels in food webs and food chains: producers, primary consumers, secondary consumers, tertiary consumers and quaternary consumers

Explain why the transfer of energy from one trophic level to another is often not efficient

Explain, in terms of energy loss, why food chains usually have fewer than five trophic levels

Explain why it is more energy efficient for humans to eat crop plants than to eat livestock that have been fed on crop plants

Describe the carbon cycle, limited to: photosynthesis, respiration, feeding, decomposition, formation of fossil fuels and combustion

Describe an ecosystem as a unit containing the community of organisms and their environment, interacting together 

Describe biodiversity as the number of different species that live in an area 

Describe the reasons for habitat destruction, including:

State the undesirable effects of deforestation as an example of habitat destruction, to include: reducing biodiversity, extinction, loss of soil, flooding and increase of carbon dioxide in the atmosphere

Explain the undesirable effects of deforestation as an example of habitat destruction, to include: reducing biodiversity, extinction, loss of soil, flooding and increase of carbon dioxide in the atmosphere

Explain why organisms become endangered or extinct, including: climate change, habitat destruction, hunting, overharvesting, pollution and introduced species

Describe how endangered species can be conserved, limited to:

movement as an action by an organism or part of an organism causing a change of position or place

respiration as the chemical reactions in cells that break down nutrient molecules and release energy for metabolism

sensitivity as the ability to detect and respond to changes in the internal or external environment

growth as a permanent increase in size and dry mass

reproduction as the processes that make more of the same kind of organism 

excretion as the removal of waste products of metabolism and substances in excess of requirements

nutrition as the taking in of materials for energy, growth and development

ciliated cells – movement of mucus in the trachea and bronchi

root hair cells – absorption

palisade mesophyll cells – photosynthesis

neurones – conduction of electrical impulses

red blood cells – transport of oxygen

sperm and egg cells (gametes) – reproduction

starch, glycogen and cellulose from glucose

proteins from amino acids 

fats and oils from fatty acids and glycerol

iodine solution test for starch

Benedict's solution test for reducing sugars

biuret test for proteins

ethanol emulsion test for fats and oils

starch as an energy store 

cellulose to build cell walls

glucose used in respiration to provide energy 

sucrose for transport in the phloem 

nectar to attract insects for pollination 

nitrate ions for making amino acids

magnesium ions for making chlorophyll

carbohydrates

fats and oils

proteins

vitamins, limited to C and D

mineral ions, limited to calcium and iron 

fibre (roughage) 

water

alimentary canal mouth, oesophagus, stomach, small intestine (duodenum and ileum) and large intestine (colon, rectum and anus)

associated organs salivary glands, pancreas, liver and gall bladder 

ingestion - the taking of substances, e.g. food and drink, into the body (b) digestion - the breakdown of food

absorption - the movement of nutrients from the intestines into the blood

assimilation - uptake and use of nutrients by cells

egestion - the removal of undigested food from the body as faeces

amylase breaks down starch to simple reducing sugars

proteases break down protein to amino acids

lipase breaks down fats and oils to fatty acids and glycerol 

xylem - transport of water and mineral ions, and support 

phloem - transport of sucrose and amino acids

sources as the parts of plants that release sucrose or amino acids

sinks as the parts of plants that use or store sucrose or amino acids

heart, limited to: vena cava, aorta, pulmonary artery and pulmonary vein 

lungs, limited to: pulmonary artery and pulmonary vein

red blood cells in transporting oxygen, including the role of haemoglobin

White blood cells in phagocytosis and antibody production

platelets in clotting (details are not required)

plasma in the transport of blood cells, ions, nutrients, urea, hormones and carbon dioxide

lymphocytes - antibody production 

phagocytes - engulfing pathogens by phagocytosis

by direct contact, including through blood and other body fluids

indirectly, including from contaminated surfaces, food, animals and air 

a clean water supply

hygienic food preparation

good personal hygiene

waste disposal 

sewage treatment (details of the stages of sewage treatment are not required)

weakened pathogens or their antigens are put into the body 

the antigens stimulate an immune response by lymphocytes which produce antibodies

memory cells are produced that give long-term immunity

continuation of fast heart rate to transport lactic acid in the blood from the muscles to the liver

continuation of deeper and faster breathing to supply oxygen for aerobic respiration of lactic acid

aerobic respiration of lactic acid in the liver

the central nervous system (CNS) consisting of the brain and spinal cord

the peripheral nervous system (PNS) consisting of the nerves outside of the brain and spinal cord

adrenal glands and adrenaline 

pancreas and insulin 

testes and testosterone

ovaries and oestrogen 

increased breathing rate 

increased heart rate 

increased pupil diameter

insulation, sweating, shivering, the role of the brain

vasodilation and vasoconstriction of arterioles supplying skin surface capillaries

genetic variation within populations 

production of many offspring 

struggle for survival, including competition for resources

a greater chance of reproduction by individuals that are better adapted to the environment than others

these individuals passing on their alleles to the next generation

selection by humans of individuals with desirable features

crossing these individuals to produce the next generation 

selection of offspring showing the desirable features

increased area for housing, crop plant production and livestock production

extraction of natural resources 

freshwater and marine pollution 

detailed description of eutrophication is not required) 

monitoring and protecting species and habitats

education

captive breeding programmes 

seed banks