Biology GCSE
Biology GCSE glossary
43 key terms for Biology GCSE, A to Z, each linked to the topic pages that use it.
A
- Active Transport
- The movement of substances from a region of lower concentration to a region of higher concentration (against the concentration gradient) using energy from…Pearson Edexcel
- Alveoli
- Tiny air sacs in the lungs adapted for efficient gas exchange.Pearson Edexcel
- Antibody
- A protein produced by lymphocytes that is complementary in shape to a specific antigen, binding to it to neutralise the pathogen.Pearson Edexcel
- Antigen
- A unique protein on the surface of a cell or pathogen that induces an immune response.Pearson Edexcel
- Aseptic technique
- Methods used to prevent contamination by unwanted microorganisms during laboratory experiments.Pearson Edexcel
B
- Biomass
- The mass of living material in an organism, which represents the chemical energy stored within it.Pearson Edexcel
C
- Coronary Artery
- The blood vessels that supply the heart muscle tissue itself with oxygenated blood.Pearson Edexcel
D
- Decomposer
- Microorganisms (bacteria and fungi) that break down dead plant and animal matter by secreting enzymes into the environment.Pearson Edexcel
- Differentiation
- The process by which an unspecialised cell becomes specialised to perform a specific function.Pearson Edexcel
- Diffusion
- The net movement of particles from an area of higher concentration to an area of lower concentration.Pearson Edexcel
- DNA Ligase
- An enzyme used to join the sticky ends of the target gene and the plasmid DNA together.Pearson Edexcel
- Double Circulatory System
- A system where blood passes through the heart twice for every complete circuit of the body.Pearson Edexcel
- Double-blind trial
- A clinical trial where neither the patients nor the doctors know who has been given the real drug and who has been given the placebo.Pearson Edexcel
E
- Ecosystem
- The interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment.Pearson Edexcel
- Eutrophication
- The hyper-nutrition of a body of water (usually by nitrate fertilisers) leading to algal blooms, oxygen depletion, and death of aquatic life.Pearson Edexcel
G
- Genetic Modification
- The artificial transfer of a gene from one organism into the genome of another organism.Pearson Edexcel
H
- Haemoglobin
- The red pigment found in red blood cells that binds reversibly to oxygen.Pearson Edexcel
- Health
- A state of complete physical, mental, and social well-being, and not merely the absence of disease or infirmity.Pearson Edexcel
- Homeostasis
- The regulation of the internal conditions of a cell or organism to maintain optimum conditions for function, in response to internal and external changes.Pearson Edexcel
- Hormone
- A chemical messenger secreted by an endocrine gland directly into the bloodstream, which produces an effect on target organs.Pearson Edexcel
M
- Mitosis
- A type of cell division that produces two genetically identical diploid daughter cells.Pearson Edexcel
- Mutation
- A random change in the DNA sequence of an organism.Pearson Edexcel
- Myelin Sheath
- A fatty layer surrounding the axon of a neurone that acts as an electrical insulator and speeds up impulse transmission.Pearson Edexcel
N
- Natural Selection
- The process by which individuals that are better adapted to their environment survive and reproduce, passing on their advantageous alleles.Pearson Edexcel
- Negative Feedback
- A control mechanism that reacts to a change in a condition by trying to bring the condition back to a normal level.Pearson Edexcel
- Nitrifying Bacteria
- Bacteria in the soil that convert ammonium ions into nitrites, and then into nitrates.Pearson Edexcel
O
- Osmosis
- The net movement of water molecules from a region of higher water potential to a region of lower water potential through a partially permeable membrane.Pearson Edexcel
P
- Pathogen
- A microorganism that causes infectious disease.Pearson Edexcel
- Phagocytosis
- The process by which white blood cells (phagocytes) engulf and digest pathogens.Pearson Edexcel
- Phototropism
- A plant's growth response to light, controlled by the unequal distribution of auxin.Pearson Edexcel
- Placebo
- A substance that looks exactly like the real medicine but contains no active drug, used as a control in clinical trials.Pearson Edexcel
- Plasma
- The pale yellow liquid component of blood that transports dissolved substances.Pearson Edexcel
R
- Reflex Action
- A rapid, automatic response to a stimulus that does not involve the conscious part of the brain.Pearson Edexcel
- Reflex Arc
- The nerve pathway involved in a reflex action, bypassing conscious areas of the brain for a faster response.Pearson Edexcel
- Restriction Enzyme
- An enzyme that cuts DNA at a specific sequence, often leaving sticky ends.Pearson Edexcel
S
- Stem Cell
- An unspecialised cell that can divide and differentiate into different types of specialised cells.Pearson Edexcel
- Stomata
- Tiny pores on the surface of a leaf (usually the lower epidermis) that allow for gas exchange and transpiration.Pearson Edexcel
- Synapse
- The junction between two neurones where chemicals (neurotransmitters) diffuse across the gap to transmit the signal.Pearson Edexcel
T
- Translocation
- The movement of dissolved sugars and amino acids through the phloem tissue from sources (leaves) to sinks (roots, growing regions).Pearson Edexcel
- Transpiration
- The loss of water vapour from the leaves of a plant, primarily through the stomata.Pearson Edexcel
- Trophic Level
- A specific feeding stage or position within a food chain or food web.Pearson Edexcel
- Type 1 Diabetes
- A disorder in which the pancreas fails to produce sufficient insulin, leading to uncontrolled high blood glucose levels.Pearson Edexcel
V
- Vector
- An organism that carries and transmits a pathogen to a host without suffering from the disease itself (e.g., a mosquito carrying malaria).Pearson Edexcel
Where these terms come from
Each definition is one we publish on a Biology GCSE topic page or study guide. Open a term to see how each exam board words it and which topic it belongs to. For the full course, go to Biology revision or the glossary for every subject.
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