CCEA GCSE Biology - Denmour Boyd, James Napier 2017
Glossary
Abiotic factor A physical (non-living) factor which affects an organism
Absorption The ability of cells to take in substances through their cell membrane
Active immunity A type of immunity produced by the body producing antibodies
Active site The part of an enzyme molecule into which the substrate molecule fits because they have complementary shapes
Active uptake (transport) A process which uses energy released by respiration to move substances from a low concentration to a high concentration
Aerobic A chemical process which requires oxygen
Algal bloom The excessive growth of green algae on the surface of lakes and rivers
Allele One of two possible versions of a particular gene
Alveolus A single bubble-shaped air space in the lungs
Amino acids A group of twenty molecules which join together to form proteins
Amniocentesis A process in which foetal cells are obtained from the amniotic fluid and then examined for the presence of genetic abnormalities
Amnion The lining that contains the amniotic fluid
Amniotic fluid The fluid within the amnion, which cushions the foetus
Anaerobic A chemical process which can take place in the absence of oxygen
Angioplasty The process in which dye is injected into the blood to allow examination of (diseased) blood vessels
Antibiotic A chemical produced by fungi that kills bacteria
Antibiotic-resistance An antibiotic-resistant bacterium cannot be killed by (at least one type of) antibiotic
Antibody A structure produced by lymphocytes that has a complementary shape (and can attach to) the antigens on a particular microorganism
Antidiuretic hormone A chemical messenger molecule, produced in the brain which controls the amount of water reabsorbed by the kidneys
Antigen A distinctive marker on a microorganism that leads to the body producing specific antibodies
Aorta The blood vessel that carries oxygenated blood from the heart to the body
Apical Refers to the tip of a plant shoot or root
Artery A blood vessel that carries blood under high pressure away from the heart
Aseptic technique The procedures used to prevent contamination when culturing microorganisms in the laboratory
Auxin A plant hormone which controls the growth of plant cells
Axon The extension of the neurone that gives a neurone its long length (and its ability to transmit nerve impulses over a long distance)
Bacteria A group of microorganisms which have a cell wall without cellulose and no nucleus
Base triplet A sequence of three bases in DNA that codes for a particular amino acid
Belt transect A method of sampling used when a habitat changes from one side to the other
Benign tumour A tumour that is surrounded by a capsule and does not spread around the body
Biodiversity The variety of living organisms in an area
Biotic factor A factor caused by the living organisms in an area
Blood pressure The force exerted by blood in the heart and the circulatory system
Booster vaccination A second (additional) vaccination that is given in a vaccination programme to combat a particular disease
Breathing rate The number of breaths per unit time
Bronchitis The narrowing of the airways in the lungs, usually caused by smoking tobacco
Cancer Uncontrolled cell division
Capillary A very thin blood vessel through which the exchange of material between blood and cells takes place
Carbohydrate A type of food molecule, including sugars, starch and cellulose, that are made up of only carbon, hydrogen and oxygen and are the main source of energy in the diet
Carbon cycle The cycling of carbon-containing substances in the environment
Cardiac output The volume (amount) of blood the heart pumps per minute
Catalyst Something which speeds up the rate of a reaction but is unchanged by the reaction
Cell The basic building block in the structure and function of living things
Cell lysis The bursting of a cell due to too much water being taken in by osmosis
Cell membrane The membrane bounding the outside of living cells controlling the substances entering and leaving the cell
Cell sap The liquid found in cell vacuoles
Cellulose A complex carbohydrate molecule found in plant cell walls
Cell wall A stiff layer outside the cell membrane of plant, bacterial and fungal cells which provides support
Central Nervous System The term referring to the coordinator in the nervous system, i.e. the brain and the spinal cord
Cervix The opening of the uterus
Chemotherapy A form of cancer treatment in which drugs are used to kill cancer cells
Chlorophyll A green coloured chemical in chloroplasts which contains magnesium and is responsible for absorbing light energy during photosynthesis
Chloroplast A structure in the cytoplasm of plant cells which contains chlorophyll and carries out photosynthesis
Chromosomes Genetic structures usually occurring in functional pairs in the nucleus of cells (except gametes and bacteria)
Circulatory system The body system that includes the heart and blood vessels
Clinical trials The stages involved in testing drugs and medicines that use human volunteers
Cloning A laboratory process which uses a single cell to grow a group of genetically identical cells or organisms
Communicable disease A disease that can be passed from one organism (person) to another
Community All the species normally found in a habitat
Compensation point Occurs in a plant when the environmental conditions [temperature, light intensity and carbon dioxide concentration] cause the rate of photosynthesis to equal the rate of respiration, resulting in no net gas exchange
Competition The interaction between two or more organisms as they try to get sufficient resources to survive
Complementary Shapes which fit into each other as in an enzyme and its substrate
Concentration gradient The difference in the concentration of a molecule or ion present in one area compared to another area
Condom A barrier contraceptive method
Consumer An animal that gains its food from consuming other organisms
Continuous variation The type of variation characterised by gradual change in a characteristic across a population
Contraception A method used to try to avoid pregnancy
Contraceptive pill A contraceptive tablet containing hormones and prevents pregnancy by affecting hormone levels thereby preventing eggs being released
Coordinator A part of the nervous system (i.e. brain or spinal cord) that links receptors and effectors
Coronary artery The very narrow arteries that supply the heart tissue with glucose and oxygen
Cuticle A waxy layer on the outer surface of a plant epidermis cell, allowing light through while reducing water loss
Cystic fibrosis A genetic condition caused by having two recessive alleles of a particular gene
Cytoplasm The contents of a cell between the cell membrane and the nucleus where chemical reactions take place
Decomposers An organism which breaks down the tissues of dead organisms and excretory products
Deforestation The cutting down of trees
Denaturation An irreversible change in the shape of an enzyme which means it is no longer complementary to the substrate and cannot catalyse the reaction
Denitrification A process carried out by bacteria in anaerobic conditions which changes nitrates into nitrogen gas
Destarch A procedure which removes stored starch from plants
Diabetes (type 2) A disease that develops in older people, associated with poor diet and obesity, in which they have difficulty controlling the concentration of their blood glucose because the insulin they produce does not work effectively
Diaphragm A muscular sheet between the thorax and abdomen which helps bring about breathing
Differentiate The ability of a cell to change into a specialised cell with adaptations to a particular function
Diffusion The movement of molecules or ions from where they are in high concentration to where they are in a lower concentration
Digestion Enzymes breaking down large, complex food molecules into small, simple soluble ones which can be absorbed
Diploid The normal chromosome number
Discontinuous variation The type of variation in which all the individuals can be clearly divided into two or more groups and there are no intermediate states
DNA The molecule that forms genes and chromosomes
Dominant In the heterozygous condition, the dominant allele will override the recessive allele
Double circulation The type of circulation in humans in which blood travels through the heart twice for each complete circulation of the body
Double helix The structure of DNA
Downstreaming The term used to describe the extraction, purification and packaging of insulin during genetic engineering
Down’s Syndrome A genetic condition in humans caused by having one extra (47) chromosome
Ecosystem An area in which a community of organisms interact with each other and their physical surroundings
Effector An organ (a muscle or gland) which responds to a stimulus by causing a change
Egested The removal of faeces
Egg (ovum) A female gamete
Electron microscope A microscope which uses a beam of electrons instead of light and allows much greater detail of cells to be visible
Emphysema Damage to the gas exchange surfaces in the lungs, usually caused by cigarette smoke
Endothermic A chemical reaction that absorbs heat
Energy flow The transfer of energy between the trophic levels in food chains and food webs
Environment The conditions which surround and effect an organism in their habitat
Enzyme specificity The ability of an enzyme to catalyse only one type of substrate
Epidermis An outer layer of cells
Eutrophication The process occurring in areas of fresh water which have too many nitrates, leading to the death of animal species
Evolution The change in a species over time—evolution also leads to the formation of new species
Excretory system An organ system which removes wastes from the body
Exothermic A chemical reaction which releases heat
Extinction A species is extinct if there are no living members of that species left
Fatty acids Long chain molecules which join to glycerol to form fats and oils (lipids)
Female sterilisation The cutting of the oviducts to prevent pregnancy
Fertilisation The fusion (joining) of a haploid sperm cell and a haploid egg cell to form a diploid zygote
Fertiliser A substance, either a waste product from animals (natural fertiliser) or produced by the chemical industry (artificial fertiliser), which provides plants with the chemicals they need to grow
Field of view The circle of light visible in a light microscope
Flagellum The tail of a sperm used for movement
Food chain A sequence of organisms which feed off each other, passing nutrients and energy
Food web A number of interlinked food chains
Fossil The remains of a living organism that has been preserved (usually in rocks) for millions of years
Gamete Sex cell that contains only one chromosome from each pair
Gas exchange The movements of gases between an organism and its surroundings
Gene Short section of DNA (chromosome) that codes for a particular characteristic
Genetic condition A condition caused by problems in genes or chromosomes
Genetic engineering The deliberate modification of the genome (DNA) in an organism to introduce desirable effects
Genetic screening A process used to test people for the presence of particular harmful alleles or other genetic abnormalities
Genome The entire genetic material (all the DNA) in an organism
Genotype The genetic make-up of an organism represented by symbols (letters), e.g. tt
Global warming The rise in the Earth’s temperature
Glycerol A molecule which makes up part of all fats (lipids)
Glycogen A complex carbohydrate molecule used for storage in animals
Habitat The place where an organism or population is normally found
Haemoglobin A molecule containing iron that is found in red blood cells
Haemophilia A sex-linked conditions that is almost exclusively found in males
Haploid A cell or nucleus with half the normal number of chromosomes
Heart disease Any disease which prevents the heart from functioning normally
Heart valve A structure in the heart that prevents the backflow of blood
Heterozygous The two alleles of a gene are different (one dominant and one recessive allele)
Homeostasis The ability of the body to maintain an almost constant internal environment
Homozygous The two alleles of a gene are the same
Huntington’s disease A genetic condition caused by the presence of a dominant allele of a particular gene
Ileum The longest part of the small intestine
Immunity Freedom from disease
Immunotherapy A form of treatment of cancer in which antibodies are injected into the patient. The antibodies attach to cancer cells and help the body’s immune system destroy the cancer cells
Implantation The term describing the attachment of the ball of cells (embryo) following fertilisation to the uterus lining
Independent assortment A process that takes place during meiosis, in which chromosomes are reassorted in the formation of gametes
Indicator species A species which can be used to monitor the level of pollution in a habitat
Infertility The inability of someone to have children
Inhibitor A molecule which fits into the active site of an enzyme and stops the normal substrate entering so reducing the reaction rate of the enzyme
Intercellular space A space between cells as in a leaf
Intercostal muscles The muscles in the chest wall that contract and cause the ribs to move out thereby increasing the volume of the thorax during breathing
In-vitro fertilisation Fertilisation outside the body
In-vitro testing Testing of medicines and drugs in the laboratory
Kinetic energy The energy of movement
Left atrium The heart chamber that receives blood from the lungs
Left ventricle The heart chamber that pumps blood around the body
Legume A group of plants including peas, beans and clover
Lethargy Tiredness, a total lack of energy
Leukaemia A type of cancer in which some types of blood cells increase out of control
Limiting factors Any factor which affects a chemical process such as photosynthesis and is at a level less than optimum will slow or limit the process
Lipid A fat or oil molecule
Lock and key model Model used to explain how an enzyme reacts with its substrate
Lymphocyte A type of white blood cell that produces antibodies
Lysis The process that describes the rupturing of an animal cell when it takes in too much water by osmosis
Magnification The number of times the length of an image is larger than the actual length of the object
Male sterilisation The cutting of the sperm tubes (vasectomy) to prevent pregnancy
Malignant tumour A tumour that is not surrounded by a capsule and capable of spreading around the body
Meiosis A type of cell division that produces cells (gametes) that have half the normal chromosome number (haploid cells)
Memory lymphocyte A special type of lymphocyte that can remain in the body for many years and produce antibodies quickly when required
Menstrual cycle The monthly cycle in females of reproductive age that prepares the body for pregnancy
Meristem Cells at the tip (apex) of a plant stem or root which constantly divide to form new cells
Mesophytic Land plants which grow in temperate climates
Mitochondria Structures in the cytoplasm where the reactions of respiration occur
Mitosis A type of cell division that produces cells genetically identical to the parent cell and to each other
MRSA A type of bacterium that is resistant to most antibiotics
Multi-celled An organism made up of many cells
Mutation Random change in the number of chromosomes or type of gene
Myelin sheath A fatty layer around the axon that both acts as an insulator and speeds up nerve impulses
Natural selection The process in which the better adapted individuals survive (at the expense of the less well adapted individuals) and pass on their genes to their offspring
Negative feedback A process involved in homeostasis which, by constant monitoring of an internal factor in the body, causes any change to be reversed, bringing the factor back to normal values
Nerve impulses Small electrical charges that pass along neurones
Neurones The cells (also called nerve cells) of the nervous system
Nicotine The addictive substance in tobacco smoke, which also affects heart rate
Nitrifying bacteria Bacteria that convert ammonium compounds to nitrates in the nitrogen cycle
Nitrogen fixation A process which allows bacteria to change nitrogen gas into nitrates
Nuclear membrane The membrane surrounding the nucleus
Nucleus The large structure in a cell containing chromosomes
Nutrient cycle The cycling of substances (e.g. nutrients and elements) in the environment
Obesity Being extremely overweight
Oestrogen The female sex hormone produced by the ovaries, which both causes the repair and build-up of the uterus lining following menstruation and stimulates ovulation
Optimum The value of a factor which allows a reaction to happen at its fastest rate
Optimum dosage The best amount or concentration of a drug or medicine to use when treating patients
Osmoregulation The ability to control the amount of water in the body
Osmosis The diffusion of water molecules from a dilute solution to a more concentrated solution through a selectively permeable membrane
Ovary The female organ that produces eggs (ova)
Oviduct The structure that carries eggs (ova) from the ovary to the uterus
Ovulation The release of an egg by an ovary
Palisade mesophyll The upper of the two layers of mesophyll cells in the centre of a leaf, closely packed end on to the upper surface and containing many chloroplasts. They are the main site of photosynthesis
Passive immunity A type of immunity produced by injecting antibodies
Pedigree diagram A diagram that shows how a particular condition is inherited through the different generations in a family
Peer review A process of validation in which other scientists in the same field review research and provide feedback and/or suggest refinements
Penicillin The first antibiotic developed
Penis Organ that introduces sperm into the vagina
Percentage cover A method of estimating the amount of a plant species in a quardat
Phagocyte A type of white blood cell that destroys microorganisms by engulfing them and digesting them (phagocytosis)
Phenotype The outward appearance of an individual, e.g. tall
Photosynthesis The chemical process in green plants which uses light energy to convert carbon dioxide and water into sugars and oxygen
Phototropism A growth movement in plants in response to light
Placenta The structure that links the uterus wall to the foetus via the umbilical cord. It is here that exchange of materials takes place between the mother and the foetus
Plasma The liquid part of the blood that functions as a transport medium
Plasmid A small circular ring of DNA in a bacterium
Plasmolysis A plant cell is plasmolysed when it has lost water by osmosis and its membrane separates from the cell wall
Platelets Blood components that help convert fibrinogen to fibrin in the processes of blood clotting and scab formation
Pleural membranes These membranes line the outside of the lungs and the inside of the chest wall
Population A group of organisms of the same species living in an area
Potometer A piece of apparatus that can be used to compare rates of transpiration in different conditions and to investigate the factors affecting the rate of water uptake by a plant
Preclinical trials The stages involved in testing drugs and medicines that occur before testing on human volunteers
Primary response The response of the immune system to the first exposure of a particular type of microorganism / antigen
Producer An organism that produces food, a plant, which is at the start of a food chain
Product A molecule produced during a chemical reaction
Progesterone The female hormone that maintains the build-up of the uterus lining and prepares the uterus for pregnancy
Prostate gland The male gland that adds fluid to nourish the sperm
Protein A type of food molecule, made up of carbon, hydrogen, oxygen and nitrogen, formed by long chains of amino acids that are important in the structure and functioning of cells
Pulmonary artery The blood vessel that carries deoxygenated blood from the heart to the lungs
Pulmonary vein The blood vessel that carries oxygenated blood from the lungs to the heart
Punnett square A grid (table) used to work out the offspring in a genetic cross
Putrefying bacteria Decomposing bacteria
Pyramid of biomass A diagram showing the mass of living tissue, biomass, at each stage of a food chain
Pyramid of number A diagram showing the numbers of organisms at each stage of a food chain
Quadrat An apparatus, usually a square frame, used to sample an area
Radiotherapy The use of high energy X-rays in the treatment of cancer
Random sampling A method of sampling in which the position of each sample does not depend on the position of the previous sample and the overall sample of the area being studied is unbiased, representative
Reagent A chemical used as a test for the presence of a particular substance
Receptor A structure which can detect a change (stimulus) in the environment
Recessive An allele that will only show a characteristic if both alleles are present (and there is no dominant allele present)
Recovery rate The time taken for the breathing or heart rate to return to normal after exercise
Red blood cells Blood cells that carry oxygen around the body
Reflex action A very fast response to a stimulus by means of a nervous pathway involving a small number of nerve cells
Reliable results Results which, when repeated, are consistent
Representative sample A sample which has all the same characteristics as the whole population
Resolution The ability of a microscope to distinguish detail in an image
Respiration Respiration is the release of energy from food
Response The action of an effector
Restriction enzymes Enzymes used in genetic engineering that cut DNA at particular positions
Right atrium The heart chamber that receives blood from the vena cava
Right ventricle The heart chamber that pumps blood to the lungs
Sample A small part of an area or population
Saprophyte A bacterium or fungus which decomposes material by releasing enzymes onto the surface and absorbing the breakdown products
Scale bar A line drawn on or near a magnified image showing a given length magnified by the same amount
Scrotum Sac that holds and protects the testes
Secondary response The rapid immune response upon a second (or additional) infection by a particular microorganism
Selective breeding The selection and subsequent breeding of organisms chosen by man for their desirable characteristics
Selectively permeable The ability of a membrane to allow some substances to pass through while preventing others
Sex chromosome One of the two chromosomes that determines the sex of an individual
Sex linkage The way in which certain genetic conditions are more likely to affect a particular sex
Side effects An unwanted or unplanned effect of a drug on a person
SI units The International System of units based on the metre, kilogram and second
Specialised A cell that has adaptations to a particular function
Sperm A male gamete (sex cell) formed by meiosis
Sperm tubes The structures that carry sperm from the testes to the penis
Spongy mesophyll The lower of the two layers of mesophyll cells in the centre of a leaf, loosely arranged with airspaces. They are the main site of gas exchange
Stain A chemical which, when added to cells, colours some parts of the cells more than others making the structures more noticeable
Stem cells Simple cells in animals and plants that can continue to divide to produce more stem cells which in turn can change into one or several types of specialised cells
Stent A small mesh-like structure that is inserted into a blood vessel to keep the lumen open
Sticky end The term used to describe the overlapping (and non-paired) strand that is left when DNA is cut by a restriction enzyme
Stimulus A feature of the environment that stimulates a receptor in the nervous system
Stomata The small pores in the surface of plant leaves
Stroke A type of cardiovascular disease that affects the brain
Substrate A molecule that is acted upon by an enzyme
Superbug A type of bacterium that is resistant to a number of antibiotics
Surface area A measure of the external boundary of an object, a cell or an organism that is exposed to the environment
Surface epithelium cells A single layer of cells covering the outer surface of multi-celled organisms
Sustainable woodlands Woodlands harvested at a rate which allows them to continue growing without damaging the environment
Synapse The small junction (gap) between adjacent neurones
Transmitter substance A chemical which diffuses across a synapse
Testes The structure that produces sperm in males
Testosterone The male sex hormone produced by the testes
Thermostable enzymes Enzymes which are able to function over a wide range of temperatures without being broken down
Thorax The area between the lungs and the chest wall
Transpiration The evaporation of water from mesophyll cells followed by diffusion through air spaces and stomata
Trophic level The level at which an organism feeds in a food chain or web
Turgid (turgor) The state of a plant cell when it has gained enough water by osmosis for the cell membrane to push against the cell wall making the cell firm. Turgor provides support in plants
Umbilical cord The structure containing blood vessels that links the placenta to the foetus
Urethra The tube through which the sperm leaves the penis
Uterus The female organ in which the foetus will develop if pregnancy occurs
Vaccination The injection of dead or modified pathogens (disease-causing microorganisms) with the purpose of raising antibody and memory lymphocyte levels in the blood
Vacuole A liquid filled space in the cytoplasm of a cell which is large and permanent in plant cells
Vagina The part of the female reproductive system into which sperm is deposited during sexual intercourse
Validity The validity of experimental results depends on whether the methods used are actually testing the question asked
Vasectomy (Male sterilisation) A contraceptive method in which the sperm tubes are cut
Vein A blood vessel that carries blood back to the heart
Vena cava The vein that returns deoxygenated blood to the heart
Villi Small finger-like projections lining the wall of the ileum which increase its surface area for absorption
Volume A measure of the amount of space an object, a cell or organism occupies
Voluntary action A response to a stimulus which involves thinking
White blood cells Blood cells that help defend against disease
Zygote The first cell of the new individual following fertilisation