Cells
Learn all about cells with these GCSE biology revision videos. Revise how cells are structured, how they divide and how we can see them. We'll also explain the main differences between optical, light, and electron microscopes.
Stem cells: Where they come from and how they are used in humans and plants.
Specialisation: Cells, such as red blood cells, adapted for particular jobs within a multicellular organism. Organisation of tissues into organs and systems.
Diffusion: Movement of particles according to their concentration, how this happens in living cells, and why there is an upper size limit.
Microscopy: The main differences between optical, light, and electron microscopes.
Infection and response
Learn all about health and infection - and how the body fights against it. We'll explain different diseases, what causes foodborne illnesses, and the body's defence mechanisms.
Diseases: Prevention and treatment of malaria, which is spread by mosquitoes, and the sexually transmitted diseases chlamydia and HIV.
Foodborne illness: Four major safety precautions to inhibit the growth of bacteria such as salmonella and E. coli in cooked food.
Monoclonal antibodies: Their uses in disease detection and treatment. How they are mass produced from mouse lymphocytes and tumour cells.
Non-communicable diseases: Examples of diseases arising from environmental and lifestyle risk factors.
The body's defence mechanisms: How mucous membranes, skin and clotting factors keep diseases out, while the immune system fights any that get in.
Body systems
In this set of biology revision videos, learn about some of the processes in the human body that ensure it functions correctly. Let's learn about the impact of exercise, sex hormones and puberty, eye anatomy, and the menstrual cycle phases.
The impact of exercise: How the circulatory system improves with regular exercise.
Sex hormones and puberty: How testosterone from the testes and oestrogen from the ovaries cause physical changes, from breast growth to body hair.
Mechanics of breathing: How the muscles of the respiratory system function to allow inhalation and exhalation.
Eye anatomy: How the human eye focuses light rays onto the retina, and how this can go wrong in short- and long-sighted people.
Blood glucose: The endocrine system maintains steady blood sugar levels. Diabetes disrupts this balance and must be managed by the patient.
Menstrual cycle: The sequence of four hormones, from the pituitary gland and ovaries, that coordinate ovulation with changes in the uterus lining.
Osmoregulation: How the human body manages blood concentration through filtering and reabsorption in the kidneys, controlled by the pituitary gland.
Genetics
Watch this biology revision collection to find out about genes, DNA and genetic inheritance. Let's learn about the structure of DNA, what meiosis is, and more!
Genetic disease: Descriptions of the inherited diseases cystic fibrosis, Huntington's and haemophilia, along with the chromosomal disorder Down's syndrome.
Protein synthesis: Mechanisms used by ribosomes in cells to make proteins, according to instructions from the DNA in the nucleus.
Genetic engineering: How DNA is altered to make bacteria produce insulin for the treatment of diabetes in humans.
Structure of DNA: The sequences of base pairs that code for specific amino acids.
Meiosis: The process unique to sexual reproduction that creates sex cells to allow the DNA of both parents to be combined.
Genetic inheritance: How dominant and recessive alleles are tracked through different generations, using cats as an example.
Plants and their structures
Improve your GCSE biology knowledge by learning what photosynthesis is and how plants are structured in this collection. You can also learn about phototropism and gravitropism.
Rate of photosynthesis: Factors that limit photosynthesis, particularly light, water and carbon dioxide, and an experimental demonstration.
Phototropism and gravitropism: Growth hormones called auxins make different areas of a plant grow towards or away from light, and similarly with gravity.
Transport system in plants: The flow of water upwards through xylem in the stem and the transportation of glucose throughout the plant by the phloem.
Living processes
Many processes happen in the human body to ensure it functions correctly. Find out more about some of them in this collection of biology revision guides about food and nutrition, enzymes, and the human excretory system.
Food and nutrition: The importance of carbohydrates, fats and proteins to the body.
Enzymes: How their active sites are structured to match their substrate in a lock-and-key model, and how inhibitor molecules can slow the process down.
Human excretory system: The function of the kidneys in removing water and dissolved waste while preserving useful substances by reabsorption.
Biodiversity
Learn about what biodiversity is (the variety of plant and animal life in a particular habitat) in this revision collection and explore facts about deforestation, eutrophication, and biodiversity investigation.
Deforestation: Its negative impact on biodiversity and the climate, and how some countries have begun to manage logging to minimise the damage.
Eutrophication: The overgrowth of plants caused by pollution from excess fertiliser and why this is a bad thing.
Biodiversity investigation: A practical experiment to measure organisms in a field. Biotic and abiotic factors affecting distribution.