GCSE Biology Glossary
Learn Biology terms in context
Every term is pulled from published ExamCompanion Biology content and linked back to the topics, learning objectives, questions, flashcards, and notes where it appears.
240
published terms
A
66abstinence
The practice of refraining from sexual intercourse, particularly during the time when an egg may be present in the oviduct.
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accommodation
The process by which the eye adjusts the shape of the lens to focus on near or distant objects.
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accommodation
The process by which the eye adjusts the shape of the lens to focus on objects at different distances.
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ADH
Antidiuretic hormone (ADH) is a hormone that regulates water balance in the body by controlling the permeability of kidney tubules.
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ADH
Antidiuretic hormone (ADH) is a hormone that helps regulate water balance in the body by controlling the permeability of kidney tubules.
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adrenal glands
Glands located on top of the kidneys that produce hormones, including adrenaline, which are involved in the body's response to stress.
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adrenaline
A hormone secreted by the adrenal glands in response to fear or stress, which prepares the body for 'fight or flight' by increasing heart rate and oxygen delivery.
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adrenaline
A hormone secreted by the adrenal glands that increases heart rate and enhances oxygen and glucose delivery to the brain and muscles during stress or fear.
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adrenaline
A hormone secreted by the adrenal glands that prepares the body for 'fight or flight' responses during stress or fear.
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adrenaline
A hormone secreted by the adrenal glands in response to stress or fear, increasing heart rate and energy supply to muscles.
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advantages of asexual reproduction
Benefits of asexual reproduction include faster reproduction rates, lower time and energy costs, and the ability to produce many identical offspring in favorable conditions.
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advantages of monoclonal antibodies
Benefits of using monoclonal antibodies include their specificity to target antigens, which can lead to more effective treatments with fewer side effects.
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aerobic respiration
A type of respiration that requires oxygen and produces carbon dioxide and water as by-products, along with a high yield of energy.
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aerobic respiration
The process of cellular respiration that requires oxygen to convert glucose into carbon dioxide and water, releasing energy.
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Aerobic respiration
A type of respiration that requires oxygen to produce energy from glucose, resulting in carbon dioxide and water as byproducts.
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Aerobic respiration
A type of respiration that requires oxygen and produces a high yield of energy by fully oxidizing glucose.
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Aerobic respiration equation
The representation of aerobic respiration as a chemical reaction, specifically glucose plus oxygen produces carbon dioxide plus water.
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Alexander Fleming
A Scottish bacteriologist who discovered penicillin in 1928, marking a significant advancement in medical treatment.
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algebraic equation
An equation that involves variables and constants, which can be solved to find the value of the variables.
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allele
In Genetic inheritance, allele means the specific Unit 4.6 idea used to answer this objective: students must explain the terms allele, dominant and recessive. Keep the term curriculum-specific by applying this boundary: DNA is the molecule; a gene is a functional section of that molecule. Do not use allele as a vague inheritance word; link it to Reproduction and explain the exact role it plays in AQA GCSE Biology.
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allele
Different forms of a gene that can exist at a specific locus on a chromosome, influencing single-gene characteristics.
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Allele
In Genetic inheritance, Allele means the specific Unit 4.6 idea used to answer this objective: students must explain that different forms of a gene are called alleles. Keep the term curriculum-specific by applying this boundary: DNA is the molecule; a gene is a functional section of that molecule. Do not use Allele as a vague inheritance word; link it to Reproduction and explain the exact role it plays in AQA GCSE Biology.
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Allele
A variant form of a gene that occupies a specific position on a chromosome and can influence a particular trait.
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amino acid
The building blocks of proteins, each coded for by a specific sequence of three bases in DNA.
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amino acid
The organic compounds that serve as the building blocks of proteins, with their sequence determined by the order of bases in DNA.
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Amino acid sequence
The linear order of amino acids encoded by a gene’s DNA sequence, which dictates the protein’s shape and function.
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amino acids
Organic compounds that combine to form proteins, which are essential for plant growth and development, synthesized from glucose in plants.
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amino acids
The building blocks of proteins, which are produced during the digestion of proteins and cannot be stored in excess.
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amino acids
The building blocks of proteins, which are linked together in a specific sequence as determined by the gene.
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Amino acids
Organic compounds that serve as the building blocks of proteins, essential for protein synthesis and breakdown.
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ammonia
A toxic substance produced during deamination that must be converted into urea for safe excretion from the body.
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ammonia
A toxic compound produced from the breakdown of proteins that must be converted into urea for safe excretion.
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anaerobic respiration
A type of respiration that occurs without oxygen, resulting in the production of lactic acid in animals or ethanol and carbon dioxide in plants and yeast, along with a lower yield of energy.
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anaerobic respiration
A type of respiration that occurs without oxygen, resulting in the production of energy and byproducts such as lactic acid in animals or ethanol and carbon dioxide in yeast.
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Anaerobic respiration
A type of respiration that occurs without oxygen, resulting in the production of energy and by-products such as lactic acid or ethanol.
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Anaerobic respiration
A type of respiration that occurs without oxygen, producing energy from glucose and resulting in byproducts such as lactic acid or ethanol and carbon dioxide.
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Anaerobic respiration
A type of respiration that occurs without oxygen, resulting in lower energy yield and the production of by-products such as lactic acid or ethanol.
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Anaerobic respiration
A type of respiration that occurs without oxygen, resulting in the conversion of glucose to lactic acid in muscles.
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Anaerobic respiration
A type of respiration that occurs without oxygen, resulting in the production of ethanol and carbon dioxide in yeast and plants.
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Anaerobic respiration
A type of respiration that occurs in muscles when there is insufficient oxygen, resulting in the production of energy and lactic acid.
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animal (Animal and plant cells 1)
animal (Animal and plant cells 1) means the curriculum-specific idea needed to answer: Compare plant and animal cells using key structural differences.
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antibacterial chemicals
Substances produced by plants that inhibit the growth of bacteria, aiding in the plant's defence against infections.
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antibacterial chemicals
Substances produced by plants that inhibit the growth of bacteria, helping to protect the plant from infections.
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antibiotic resistance
The ability of bacteria, such as those causing gonorrhoea, to survive and multiply despite the presence of antibiotics like penicillin.
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antibiotic resistance
The ability of bacteria to survive and grow in the presence of antibiotics that would normally kill them or inhibit their growth.
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antibiotics
Medications used to treat bacterial infections, including gonorrhoea, by killing or inhibiting the growth of bacteria.
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antibiotics
Medicines used to treat bacterial infections by killing or inhibiting the growth of bacteria.
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antibiotics
Medicines that help to cure bacterial diseases by killing infective bacteria inside the body.
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antibiotics
Medicines that help to cure bacterial infections by killing or inhibiting the growth of bacteria.
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antibiotics
Medicines that are used to treat bacterial infections by killing or inhibiting the growth of bacteria.
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antibodies
Proteins produced by white blood cells that specifically target and neutralize pathogens.
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antibodies
Proteins produced by white blood cells that identify and neutralize pathogens such as bacteria and viruses.
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Antibodies
Proteins produced by hybridoma cells that specifically bind to antigens, used in various diagnostic and therapeutic applications.
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antibody production
The process by which lymphocytes are activated to create antibodies in response to specific antigens.
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Apply
In AQA GCSE Biology, Apply means use the scientific idea in a new context or data example rather than only recalling it. For Animal tissues, organs and organ systems, use Apply to support the objective to apply sampling ideas to data about risk factors. Related approved keywords for this objective include risk factors. This definition is deliberately scoped to The effect of lifestyle on some non-communicable diseases, so it preserves this concept without merging it with neighbouring key terms.
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Artificial selection
The intentional selection of organisms with specific characteristics for breeding, used by humans to enhance crop yields and livestock quality.
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asexual reproduction
A form of reproduction that involves only one parent, does not involve the fusion of gametes, and results in offspring that are genetically identical to the parent.
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asexual reproduction
A form of reproduction involving a single parent that produces genetically identical offspring without the fusion of gametes.
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asexual reproduction
A form of reproduction involving a single parent that produces genetically identical offspring without the fusion of gametes.
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asexual reproduction
A reproductive process that involves only one parent, does not require gamete fusion, and produces genetically identical offspring.
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asexual reproduction
A form of reproduction involving one parent that produces genetically identical offspring without the fusion of gametes.
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asexual reproduction
A reproductive process that involves only one parent, does not require gamete fusion, and produces genetically identical offspring.
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automatic response
A quick reaction to a stimulus that does not involve conscious decision-making, allowing for immediate protective actions.
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auxin
A plant hormone that regulates growth by promoting cell elongation, particularly in shoots and roots.
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auxins
Plant hormones that promote root formation and are used as rooting powders for plant cuttings.
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auxins
Plant hormones that promote root formation and are used in tissue culture to encourage growth.
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B
26bacterial disease
An illness caused by bacteria, which can be transmitted through various means, including sexual contact.
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bacterial infection
An infection caused by bacteria that can be treated with antibiotics, depending on the specific strain.
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bark
The protective outer layer of stems in trees, consisting of dead cells that help shield the plant from environmental threats.
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barrier methods
Contraceptive methods that physically prevent sperm from reaching an egg, including condoms and diaphragms.
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basal metabolic rate
The rate of energy expenditure per unit time by endothermic animals at rest in a neutrally temperate environment.
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Base pairing rule
The principle that dictates which bases pair together in DNA: C↔G and A↔T, ensuring accurate replication and transcription of genetic information.
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bases
The building blocks of DNA, consisting of adenine (A), cytosine (C), guanine (G), and thymine (T), which determine the genetic code.
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behavioural contraception
Methods of contraception that rely on changes in sexual behavior to prevent pregnancy, such as abstaining from intercourse.
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binding site
The specific region on a protein antigen where a monoclonal antibody attaches, allowing for targeted interaction.
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biodiversity
The variety of life in the world or in a particular habitat or ecosystem, which can be affected by the use of plant hormones in agriculture and horticulture.
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biomolecules
Organic molecules that are essential for life, including carbohydrates, proteins, and lipids, which can be tested for using qualitative reagents.
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Black Spot
A fungal disease that affects roses and other plants, characterized by black spots on leaves, leading to leaf drop.
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blood glucose concentration
The level of glucose present in the blood, which is regulated by homeostasis to provide energy for cellular functions.
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blood glucose concentration
Blood glucose concentration refers to the amount of glucose present in the bloodstream, which needs to be maintained within a specific range for proper bodily function.
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blood glucose concentration
The level of glucose present in the blood, which is monitored and regulated by hormones such as insulin and glucagon.
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Blood glucose concentration
The level of glucose present in the blood, which is controlled by the pancreas to maintain homeostasis.
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body fluids
Fluids such as blood, semen, and vaginal secretions that can carry the HIV virus and facilitate its transmission.
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body temperature
The internal temperature of an organism, maintained within a narrow range by homeostatic mechanisms to ensure optimal enzyme activity and metabolic processes.
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body temperature
An internal condition that is maintained within a narrow range to ensure proper physiological function.
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brain complexity
The intricate structure and function of the brain, which consists of billions of interconnected neurones, making it challenging to study and treat disorders.
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brain damage
Injury to the brain that can affect cognitive, physical, and emotional functions, often studied to understand brain function.
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brain procedures
Medical interventions performed on the brain to treat disorders or injuries, which can have both benefits and risks.
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breath volume
The amount of air inhaled or exhaled in one breath, which increases during exercise to provide more oxygen to the body.
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breathing rate
The number of breaths taken per minute, which increases during exercise to enhance oxygen supply to muscles.
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bronchi
The bronchi are the two main branches of the trachea that lead into the lungs, acting as non-specific defence systems by trapping and expelling pathogens.
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bulb division
A form of asexual reproduction in which a bulb, a storage organ, divides to produce new plants, as seen in daffodils.
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C
52carbohydrate-controlled diet
A dietary approach that limits carbohydrate intake to help manage blood glucose levels, particularly in individuals with Type 2 diabetes.
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carbohydrates
Organic compounds made up of carbon, hydrogen, and oxygen, which are crucial for energy storage and supply in living organisms.
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carbon dioxide concentration
The amount of carbon dioxide present in the environment, which influences the rate of photosynthesis in plants.
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cells (Cell differentiation 1)
cells (Cell differentiation 1) means the curriculum-specific idea needed to answer: Describe how specialised cells are adapted for their function.
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cellular respiration
The process by which cells convert glucose and oxygen into energy, carbon dioxide, and water, occurring continuously in living cells.
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cellulose
A complex carbohydrate formed from glucose that provides structural support in plant cell walls.
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cellulose cell walls
The rigid outer layer of plant cells that provides structural support and helps resist invasion by microorganisms.
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cellulose cell walls
Cellulose cell walls are rigid structures that provide support and protection to plant cells, helping to resist invasion by microorganisms.
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central nervous system
The part of the nervous system that consists of the brain and spinal cord, responsible for processing information and coordinating responses.
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cerebellum
The region of the brain responsible for coordinating muscular activity and maintaining balance.
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cerebral cortex
The region of the brain associated with consciousness, intelligence, memory, and language.
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chemical extraction
The process of obtaining a substance from a plant or other source, which can be the starting point for developing new drugs.
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chemical messengers
Substances, such as hormones, that transmit signals between cells and organs to regulate physiological processes in the body.
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chemical plant defence responses
Responses by plants that involve the production of chemicals to protect against pathogens and herbivores.
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chemical reactions
Processes that involve the transformation of substances, necessary for building larger molecules in organisms.
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chemical responses
Responses involving the release of hormones or other chemicals to regulate physiological processes in the body.
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chemical symbols
Abbreviations used to represent elements and compounds in chemical equations, such as CO2 for carbon dioxide, H2O for water, O2 for oxygen, and C6H12O6 for glucose.
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Chemical symbols
Symbols used to represent elements and compounds, such as C6H12O6 for glucose, O2 for oxygen, CO2 for carbon dioxide, and H2O for water in the context of aerobic respiration.
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chlorophyll
A green pigment found in plants that is essential for photosynthesis, as it absorbs light energy.
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chloroplasts
Organelles in plant cells where photosynthesis occurs, converting light energy into chemical energy.
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chlorosis
A physiological condition in plants characterized by yellowing of leaf tissue due to insufficient chlorophyll, often caused by nutrient deficiencies such as magnesium.
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chromosome
A thread‑like structure found in the nucleus of a cell that contains DNA and proteins, and which carries genetic information.
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chromosome
A chromosome is a structure within the cell nucleus that contains DNA and carries genetic information.
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Chromosome
A thread‑like structure made of DNA and protein that carries genes and determines the genetic information passed from parent to offspring.
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chromosome behaviour
The specific actions and arrangements of chromosomes during the stages of meiosis, including pairing, crossing over, and segregation.
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chromosome pairs
Ordinary human body cells contain 23 pairs of chromosomes, which include 22 pairs that control characteristics and one pair that determines sex.
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chromosome pairs
Pairs of chromosomes that contain genes controlling various characteristics of an organism.
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chromosomes
Thread‑like structures within the nucleus that carry genetic material; in fertilisation the combined set from both gametes restores the full chromosome complement.
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ciliary muscles
Muscles that control the shape of the lens during accommodation by contracting or relaxing.
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ciliary muscles
Muscles that control the shape of the lens in the eye, enabling accommodation for focusing on objects at varying distances.
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ciliary muscles
Muscles that control the shape of the lens in the eye, allowing for focusing on near and distant objects.
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clinical testing
The phase of drug development that involves testing new medicines on human participants to evaluate their safety, effectiveness, and optimal dosing.
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clinical trials
Research studies that test new drugs on healthy volunteers and patients to assess their safety and efficacy.
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clinical trials
Research studies that test new drugs on human participants to assess their safety and effectiveness.
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clones
In Sexual and asexual reproduction, clones means the specific Unit 4.6 idea used to answer this objective: students must explain that asexual reproduction produces genetically identical offspring called clones and involves only mitosis. Keep the term curriculum-specific by applying this boundary: DNA is the molecule; a gene is a functional section of that molecule. Do not use clones as a vague inheritance word; link it to Reproduction and explain the exact role it plays in AQA GCSE Biology.
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cloning
The process of producing many identical cells from a single hybridoma cell to generate a large quantity of monoclonal antibodies.
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Coding DNA
The portion of a gene’s DNA sequence that is transcribed into mRNA and translated into a protein, determining the amino acid sequence of that protein.
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Complementary base pairing
The specific matching of nitrogenous bases in DNA, where cytosine (C) pairs with guanine (G) and thymine (T) pairs with adenine (A), forming the double‑helix structure.
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complex behaviour
Actions or reactions of an organism that involve multiple processes and interactions within the brain.
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complications
Additional health problems that can arise from an illness, potentially making it more severe or fatal.
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condom
A barrier method of contraception that is worn on the penis or inside the vagina to prevent sperm from entering the uterus.
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contraception
Methods used to prevent pregnancy by inhibiting sperm from reaching an egg or preventing ovulation.
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contraception
Methods used to prevent pregnancy, which can raise personal, social, economic, and environmental considerations.
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contraceptive methods
Various techniques, including hormonal methods like injections and implants, that prevent pregnancy by inhibiting egg maturation and release.
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control variables
Factors that are kept constant during an experiment to ensure that the results are valid and reliable.
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control variables
Factors that are kept constant during an experiment to ensure that the results are valid.
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controlled variables
Factors that are kept constant during an experiment to ensure that the results are valid.
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coordination
The process by which the nervous system organizes and integrates sensory information to produce appropriate behavioral responses.
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coordination
The process by which plant hormones work together to control and direct plant growth and responses to stimuli.
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coordination centres
Structures such as the brain, spinal cord, and pancreas that receive and process information from receptors.
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cost effectiveness
A measure of how economically a resource, such as heat, light, or carbon dioxide, can be used to enhance plant growth in greenhouses.
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cystic fibrosis
An inherited disorder that affects the cell membranes, caused by a recessive allele.
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D
40data interpretation
The process of analyzing and making sense of data collected from experiments, particularly in the context of nervous system responses.
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data representation
The method of displaying information in numerical or graphical formats to facilitate analysis.
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deamination
The process in the liver where the amino group is removed from excess amino acids, resulting in the production of ammonia.
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defence mechanisms
The processes and structures, such as white blood cells and antibodies, that protect the body from disease-causing organisms.
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deletions
Deletions are mutations where one or more nucleotide bases are removed from the DNA sequence, which can lead to changes in the resulting protein.
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delicate nature
The sensitivity of brain tissue, which requires careful handling during investigations and treatments to avoid damage.
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Describe
In AQA GCSE Biology, Describe means state the relevant features, sequence, structure, or observations clearly without needing a full cause-and-effect explanation. For Animal tissues, organs and organ systems, use Describe to support the objective to describe the role of enzymes as biological catalysts in digestion. Related approved keywords for this objective include enzymes. This definition is deliberately scoped to The human digestive system, so it preserves this concept without merging it with neighbouring key terms.
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Describe
In AQA GCSE Biology, Describe means state the relevant features, sequence, structure, or observations clearly without needing a full cause-and-effect explanation. For Animal tissues, organs and organ systems, use Describe to support the objective to describe the structure and function of the human heart in outline. Related approved keywords for this objective include heart. This definition is deliberately scoped to The heart and blood vessels, so it preserves this concept without merging it with neighbouring key terms.
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Describe
In AQA GCSE Biology, Describe means state the relevant features, sequence, structure, or observations clearly without needing a full cause-and-effect explanation. For Animal tissues, organs and organ systems, use Describe to support the objective to describe the function of plasma in transporting substances. Related approved keywords for this objective include plasma. This definition is deliberately scoped to Blood, so it preserves this concept without merging it with neighbouring key terms.
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Describe
In AQA GCSE Biology, Describe means state the relevant features, sequence, structure, or observations clearly without needing a full cause-and-effect explanation. For Animal tissues, organs and organ systems, use Describe to support the objective to describe the function of platelets in clotting. Related approved keywords for this objective include platelets. This definition is deliberately scoped to Blood, so it preserves this concept without merging it with neighbouring key terms.
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Describe
In AQA GCSE Biology, Describe means state the relevant features, sequence, structure, or observations clearly without needing a full cause-and-effect explanation. For Animal tissues, organs and organ systems, use Describe to support the objective to describe how stents help to keep coronary arteries open. Related approved keywords for this objective include stents. This definition is deliberately scoped to Coronary heart disease: a non-communicable disease, so it preserves this concept without merging it with neighbouring key terms.
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Describe
In AQA GCSE Biology, Describe means state the relevant features, sequence, structure, or observations clearly without needing a full cause-and-effect explanation. For Animal tissues, organs and organ systems, use Describe to support the objective to describe the role of donor heart or heart-lung transplants in severe heart failure. Related approved keywords for this objective include transplant. This definition is deliberately scoped to Coronary heart disease: a non-communicable disease, so it preserves this concept without merging it with neighbouring key terms.
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Describe
In AQA GCSE Biology, Describe means state the relevant features, sequence, structure, or observations clearly without needing a full cause-and-effect explanation. For Animal tissues, organs and organ systems, use Describe to support the objective to describe how different types of disease can interact. Related approved keywords for this objective include disease. This definition is deliberately scoped to Health issues, so it preserves this concept without merging it with neighbouring key terms.
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Describe
In AQA GCSE Biology, Describe means state the relevant features, sequence, structure, or observations clearly without needing a full cause-and-effect explanation. For Plant tissues, organs and systems, use Describe to support the objective to describe the role of palisade mesophyll in photosynthesis. Related approved keywords for this objective include palisade. This definition is deliberately scoped to Plant tissues, so it preserves this concept without merging it with neighbouring key terms.
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Describe
In AQA GCSE Biology, Describe means state the relevant features, sequence, structure, or observations clearly without needing a full cause-and-effect explanation. For Plant tissues, organs and systems, use Describe to support the objective to describe the role of spongy mesophyll in gas exchange. Related approved keywords for this objective include spongy mesophyll. This definition is deliberately scoped to Plant tissues, so it preserves this concept without merging it with neighbouring key terms.
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Describe
In AQA GCSE Biology, Describe means state the relevant features, sequence, structure, or observations clearly without needing a full cause-and-effect explanation. For Plant tissues, organs and systems, use Describe to support the objective to describe observation and drawing of a transverse section of a leaf as a required practical skill. Related approved keywords for this objective include leaf. This definition is deliberately scoped to Plant tissues, so it preserves this concept without merging it with neighbouring key terms.
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Describe
In AQA GCSE Biology, Describe means state the relevant features, sequence, structure, or observations clearly without needing a full cause-and-effect explanation. For Plant tissues, organs and systems, use Describe to support the objective to describe transpiration as the loss of water vapour from leaves. Related approved keywords for this objective include transpiration. This definition is deliberately scoped to Plant organ system, so it preserves this concept without merging it with neighbouring key terms.
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Describe (Animal and plant cells 1)
Describe (Animal and plant cells 1) means the curriculum-specific idea needed to answer: Describe the function of the nucleus.
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Describe (Mitosis 1)
Describe (Mitosis 1) means the curriculum-specific idea needed to answer: Describe the stages of mitosis in simple terms.
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diabetes
A medical condition characterized by high blood glucose levels due to insufficient insulin production or ineffective use of insulin by the body.
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diagnostic use
The application of monoclonal antibodies in medical tests to detect specific substances, such as hormones or pathogens, including their use in pregnancy tests.
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Direct proportion
A relationship in which the ratio of two quantities remains constant, used to predict the relative frequencies of genotypes or phenotypes in a genetic cross.
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Direct proportion
A relationship in which the ratio of two quantities remains constant; in sex‑determination crosses it means that the proportion of male to female offspring is fixed by the parental genotypes.
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discolouration
A visible change in the color of plant leaves or stems, indicating potential disease.
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disease detection
The process of identifying plant diseases through observable symptoms such as growths.
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DNA
The genetic material that carries the instructions for the development, functioning, growth, and reproduction of all known living organisms and many viruses.
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DNA
The genetic material in the nucleus of a cell, composed of two complementary strands that coil into a double‑helix structure.
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DNA
In DNA and the genome, DNA means the specific Unit 4.6 idea used to answer this objective: students must explain that DNA is contained in structures called chromosomes. Keep the term curriculum-specific by applying this boundary: DNA is the molecule; a gene is a functional section of that molecule. Do not use DNA as a vague inheritance word; link it to Reproduction and explain the exact role it plays in AQA GCSE Biology.
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DNA bases
The four nitrogenous bases that make up DNA: adenine (A), cytosine (C), guanine (G) and thymine (T).
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DNA double helix
The three‑dimensional shape of DNA, formed by two complementary strands winding around each other.
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DNA structure
The arrangement of nucleotides in a double‑helical polymer, where complementary bases (A with T, C with G) pair to form a stable sequence that determines the order of amino acids in a protein.
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dominant
In Genetic inheritance, the term dominant has a specific definition boundary role in Unit 4.6. Use dominant when students must explain the terms allele, dominant and recessive. Keep the term curriculum-specific by applying this boundary: DNA is the molecule; a gene is a functional section of that molecule. Do not use dominant as a vague inheritance word or as a synonym for a neighbouring term; link it to Reproduction, Genetic inheritance, and the exact role it plays in AQA GCSE Biology. Revision cue 1: When asking about DNA, test molecular structure, base sequence, nucleotides, or genetic information storage.
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dominant allele
An allele that is expressed in the phenotype when at least one copy is present in the genotype.
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dominant allele
A form of a gene that is expressed when at least one copy is present, masking the effect of a recessive allele.
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dominant allele
A gene variant that is expressed in the phenotype even when only one copy is present.
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Dominant allele
A form of a gene that is expressed in the phenotype when present in a single copy, masking the effect of a recessive allele.
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double blind trial
A clinical trial design in which neither the participants nor the researchers know who is receiving the treatment or the placebo, to eliminate bias.
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double helix
The double helix is the structure of DNA, formed by two strands of nucleotides twisted around each other, with bases pairing specifically (A with T and C with G).
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Double helix
The three‑dimensional shape formed when two DNA strands wind around each other, giving DNA its characteristic twisted ladder appearance.
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drug development
The process of creating new medications, which involves stages such as discovery, preclinical testing, and clinical trials.
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E
56effectors
Structures, such as muscles and glands, that bring about responses to restore optimum internal conditions.
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effectors
Structures, such as muscles and glands, that bring about responses to restore optimum internal levels.
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efficient contraction
The ability of muscles to contract effectively, which can be impaired during long periods of vigorous activity.
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electrical stimulation
A technique used to study brain function by applying electrical currents to specific brain regions to observe effects on behavior and neural activity.
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embryo screening
A medical procedure used to identify genetic disorders in embryos before implantation.
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Embryo screening
In Inherited disorders, Embryo screening means the specific Unit 4.6 idea used to answer this objective: students must consider that embryo screening and gene therapy may alleviate suffering but raise ethical issues. Keep the term curriculum-specific by applying this boundary: DNA is the molecule; a gene is a functional section of that molecule. Do not use Embryo screening as a vague inheritance word; link it to Reproduction and explain the exact role it plays in AQA GCSE Biology.
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embryo transfer
The process of placing embryos into the uterus during in vitro fertilization (IVF) to achieve pregnancy.
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emotional stress
Emotional stress refers to the psychological strain and anxiety experienced by individuals undergoing fertility treatments, such as IVF.
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endocrine glands
Glands that secrete hormones directly into the bloodstream, including the pituitary gland, pancreas, thyroid, adrenal gland, ovaries, and testes.
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endocrine system
A system of glands that secrete hormones directly into the bloodstream to regulate various bodily functions.
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endothermic reaction
A reaction that absorbs energy from the surroundings, such as photosynthesis, where light energy is used to convert carbon dioxide and water into glucose and oxygen.
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energy
The capacity to do work or produce change, essential for maintaining body functions and processes.
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energy transfer
The process by which energy produced during respiration is utilized for various living processes such as growth, movement, and maintaining body temperature.
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energy transfer
The movement of energy from glucose during respiration, which is significantly lower in anaerobic respiration than in aerobic respiration.
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energy transfer
The process by which energy released during respiration is used to power various metabolic activities within cells.
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enzyme action
The process by which enzymes catalyze biochemical reactions, which is influenced by internal conditions.
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enzyme-controlled metabolic processes
Biochemical reactions in the body that are facilitated by enzymes, utilizing energy transferred from respiration.
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ethical considerations
Moral implications and debates surrounding the use of contraception, including access, rights, and societal impacts.
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ethical considerations
The moral implications and societal values that influence the choice and acceptance of contraception methods.
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ethical considerations
Ethical considerations refer to the moral implications and societal impacts associated with the use of IVF and embryo manipulation, including issues of consent, potential for multiple births, and the status of embryos.
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ethical issues
Moral considerations and implications related to the practices and consequences of embryo screening.
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ethical issues of monoclonal antibodies
Concerns related to the use of monoclonal antibodies, including the implications of animal testing, potential side effects, and accessibility of treatments.
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Evaluate
In AQA GCSE Biology, Evaluate means use evidence, advantages, disadvantages, or limitations to make a justified judgement. For Animal tissues, organs and organ systems, use Evaluate to support the objective to evaluate risks linked to the use of blood products. Related approved keywords for this objective include blood. This definition is deliberately scoped to Blood, so it preserves this concept without merging it with neighbouring key terms.
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excess removal
The process of eliminating surplus water, ions, and urea from the body to maintain homeostasis and prevent toxicity.
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exercise
Physical activity that can improve insulin sensitivity and aid in the regulation of blood glucose levels, beneficial for individuals with Type 2 diabetes.
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exercise response
The physiological changes that occur in the body to meet the heightened energy needs during exercise.
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exothermic reaction
A chemical reaction that releases energy in the form of heat, such as cellular respiration.
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experimental results
Data collected from experiments that can be analyzed to determine the rate of photosynthesis under varying conditions.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Principles of organisation, use Explain to support the objective to explain that cells are the basic building blocks of living organisms. Related approved keywords for this objective include cells. This definition is deliberately scoped to Principles of organisation, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Principles of organisation, use Explain to support the objective to explain that an organ is made from different tissues working together to perform a function. Related approved keywords for this objective include tissues. This definition is deliberately scoped to Principles of organisation, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain that the digestive system is an organ system in which several organs work together to digest and absorb food. Related approved keywords for this objective include digestive system. This definition is deliberately scoped to The human digestive system, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain that enzyme action depends on the shape of the active site. Related approved keywords for this objective include active site. This definition is deliberately scoped to The human digestive system, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain how pH changes can affect enzyme activity. The term should be interpreted only in the context of The human digestive system. This definition is deliberately scoped to The human digestive system, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain that digestive enzymes convert large insoluble food molecules into small soluble molecules that can be absorbed into the blood. Related approved keywords for this objective include enzymes. This definition is deliberately scoped to The human digestive system, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain that bile is made in the liver and stored in the gall bladder. Related approved keywords for this objective include bile. This definition is deliberately scoped to The human digestive system, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain how bile neutralises stomach acid and emulsifies fats to increase the rate of fat digestion. Related approved keywords for this objective include bile. This definition is deliberately scoped to The human digestive system, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain that the heart pumps blood around the body in a double circulatory system. Related approved keywords for this objective include heart. This definition is deliberately scoped to The heart and blood vessels, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain the role of the right ventricle in pumping blood to the lungs. Related approved keywords for this objective include lungs. This definition is deliberately scoped to The heart and blood vessels, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain that knowledge of heart valve names is not required, but faulty valves affect blood flow. Related approved keywords for this objective include heart. This definition is deliberately scoped to The heart and blood vessels, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain how blood cells are adapted to their functions. Related approved keywords for this objective include blood. This definition is deliberately scoped to Blood, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain that coronary heart disease happens when fatty material builds up in the coronary arteries. Related approved keywords for this objective include coronary heart disease. This definition is deliberately scoped to Coronary heart disease: a non-communicable disease, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain how statins lower blood cholesterol and slow further build-up in arteries. Related approved keywords for this objective include statins. This definition is deliberately scoped to Coronary heart disease: a non-communicable disease, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain the consequences of faulty heart valves. Related approved keywords for this objective include valves. This definition is deliberately scoped to Coronary heart disease: a non-communicable disease, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain how artificial hearts can keep patients alive or support recovery while waiting for treatment. Related approved keywords for this objective include artificial heart. This definition is deliberately scoped to Coronary heart disease: a non-communicable disease, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain how defects in the immune system can increase the chance of infectious disease. Related approved keywords for this objective include disease. This definition is deliberately scoped to Health issues, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain how severe physical ill health can contribute to depression and other mental illness. Related approved keywords for this objective include health. This definition is deliberately scoped to Health issues, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain the principles of sampling as applied to epidemiological data. Related approved keywords for this objective include sampling. This definition is deliberately scoped to Health issues, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain how diet affects the incidence of non-communicable disease. Related approved keywords for this objective include diet. This definition is deliberately scoped to The effect of lifestyle on some non-communicable diseases, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain how alcohol affects the incidence of non-communicable disease. Related approved keywords for this objective include alcohol. This definition is deliberately scoped to The effect of lifestyle on some non-communicable diseases, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain how smoking affects the incidence of non-communicable disease. Related approved keywords for this objective include smoking. This definition is deliberately scoped to The effect of lifestyle on some non-communicable diseases, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain that some risk factors have proven causal mechanisms, while others are supported mainly by correlation. Related approved keywords for this objective include risk factors. This definition is deliberately scoped to The effect of lifestyle on some non-communicable diseases, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain the effects of alcohol on the liver and brain function. Related approved keywords for this objective include alcohol. This definition is deliberately scoped to The effect of lifestyle on some non-communicable diseases, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain the effects of smoking on lung disease and lung cancer. Related approved keywords for this objective include smoking. This definition is deliberately scoped to The effect of lifestyle on some non-communicable diseases, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Animal tissues, organs and organ systems, use Explain to support the objective to explain that cancer results from changes in cells that cause uncontrolled growth and division. Related approved keywords for this objective include cancer. This definition is deliberately scoped to Cancer, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Plant tissues, organs and systems, use Explain to support the objective to explain how the structures of plant tissues are related to their functions. Related approved keywords for this objective include plant tissues. This definition is deliberately scoped to Plant tissues, so it preserves this concept without merging it with neighbouring key terms.
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Explain
In AQA GCSE Biology, Explain means give a linked reason, mechanism, or cause-and-effect account rather than naming a fact. For Plant tissues, organs and systems, use Explain to support the objective to explain the role of meristem tissue at the growing tips of shoots and roots. Related approved keywords for this objective include meristem. This definition is deliberately scoped to Plant tissues, so it preserves this concept without merging it with neighbouring key terms.
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