IGCSE生物复习glossary.doc

Glossaryabdomenlower part of the body in humans, between the ribs and hip bonesabsorptionmovement of digested food molecules through the wall of the intestine into the blood or lymphacid rainAir pollution produced when acid chemicals are incorporated into rain, snow, fog or mist. The acid in acid rain comes from sulfur oxides and nitrogen oxides, products of burning coal and other fuels and from certain industrial processes.active transportmovement of ions in or out of a cell through the cell membrane, from a region of their lower concentration to a region of their higher concentration against a concentration gradient, using energy released during respirationadaptationfeatures of living things that help them survive in their environmentaerobic respirationthe release of a relatively large amount of energy in cells by the breakdown of food substances in the presence of oxygenalimentary canalthe passage along which food passes through the body, from mouth to anusalleleone of two or more alternative forms of a genealveoliair sacs in the lungs through which gas exchange takes placeamino acidthe basic building block of proteinsamnionthe innermost membrane enclosing the embryoamniotic fluidthe fluid surrounding the developing fetus that is found within the amniotic sac contained in the mothers wombamylasea digestive enzyme, produced largely by the pancreas and salivary glands, which converts starches to sugarsanaemiabelow normal levels of red blood cells or haemoglobin, or both, which can be caused by many different conditions, including iron deficiencyanaerobic respirationthe release of a relatively small amount of energy by the breakdown of food substances in the absence of oxygenantherpollen-producing oval body at the tip of a stamenantibiotica class of natural and synthetic compounds that inhibit the growth of, or kill, other micro-organismsantioxidanta molecule that is capable of reacting with free radicals and neutralising themanusthe opening to the anal canalaortathe largest artery; it leaves the heartarteryblood vessel that carries blood away from the heartarteriolesmall, elastic blood vessel that arises from arteries and leads into capillariesartificial selectionselective breedingasexual reproductionthe process resulting in the production of genetically identical offspring from one parentassimilationmaking use of molecules that have been absorbed from foodatoma chemical unit that is the smallest particle of an element still retaining its propertiesauxina type of plant hormone that elongates cells in seedlings, shoot tips, embryos and leavesaxonpart of a neurone that allows electrical signals to pass throughbacteriavery small single-celled organismsbilea liquid produced by the liver that helps in digestion of fatsbile ductthe passage from the liver to the duodenumbile saltssalts in the bile that help break fat into tiny dropletsbinomiala system in which the scientific name of an organism is made up of two parts showing the genus and speciesbiodegradableable to be broken down by bacteria and other micro-organismsbiomassthe mass of a living organismbolusa ball of foodbronchitubes through which air passes, between the trachea and the smaller bronchiolesbronchiolessmall tubes that branch from each of the bronchicaninespointed teeth used for bitingcapillariestiny blood vesselscarbohydraseenzyme that digests carbohydratecarbon dioxidegas produced during respiration and used up during photosynthesiscarnivorean animal that gets its energy by eating other animalscatalysta substance that speeds up a chemical reaction and is not changed by the reactioncell wallthe outer part of a plant cell, made of cellulosecellthe basic building block of living thingscervixthe neck of the wombchlorophyllgreen pigment in plants, involved in photosynthesischloroplastsstructures containing chlorophyllchromosomea thread of DNA, made up of a string of genesciliary musclesring of muscles holding the eye lenscodominantalleles both having an effect in a heterozygous organismcolonfirst part of the large intestinecommunityall the different species in a habitatconcentration gradienta difference in concentration across a materialconeslight-sensitive cells in the retina, responsible for colour visionconsumeran organism that gets its energy by feeding on other organismscontractionin muscle tissue, the shortening of cellscorneathe front of the eye, responsible for most of the focusingcoronary heart diseasedisease in which the coronary arteries get blocked or damagedcoronary arteriesarteries that deliver blood to the heart musclescrustaceansa group of arthropods including crabs, shrimp and woodlicecytoplasmjelly-like substance in cellsdeaminationremoval of nitrogen from amino acidsdecomposersan organism that gets its energy from dead or waste organic matterdeficiency diseasedisease caused by lack of a particular nutrientdenaturingbreakdown of an enzyme caused by a high temperaturedendritesthreads of cytoplasm in a neurone that pick up electrical signalsdenitrifying bacteriabacteria that turn ammonia and nitrates back to nitrogendialysisfiltering a patients blood in a similar way to a kidneydiaphragmmuscular sheet below the ribs and lungsdiffusionthe net movement of molecules from a region of their higher concentration to a region of their lower concentration down a concentration gradient, as a result of their random movementdigestionthe breakdown of large, insoluble food molecules into small, water-soluble molecules using mechanical and chemical processes diploid nucleusa nucleus containing two sets of chromosomes (e.g. in body cells) DNAdeoxyribonucleic acid, the molecule from which genes are composeddominantan allele that is expressed if it is present (e.g. T or G)double circulatory systema system in which the blood goes through the heart twicedrugany substance taken into the body that modifies or affects chemical reactions in the bodyduodenumfirst part of the small intestineecosystema unit containing all of the organisms and their environment, interacting together, in a given area e.g. decomposing log or a lakeeffectorsparts of the body that respond to changesegestionpassing out of food that has not been digested through the anus as faecesembryoan unborn offspring during the first eight weeks after conceptionemphysemacondition of the lungs causing breathlessnessendocrine systemcommunication system that uses hormonesenzymesproteins that function as biological catalystsepidermislayers of cells at the surface of a leafeutrophicationlack of oxygen in water caused by excessive plant nutrientsevolutionprocess by which different kinds of organism develop from earlier onesexcretionremoval from organisms of toxic materials, the waste products of metabolism (chemical reactions in cells including respiration) and substances in excess of requirements exoskeletonhard outer covering of the bodyfaeceswaste products of digestionFallopian tubetube leading from the ovary to the uterus, through which an egg must passfatty acidspart of a fat moleculefertilisationprocess by which a sperm combines with an eggfetusan unborn offspring after the first eight weeks after conceptionfibreroughage in the dietfibrinan insoluble protein that gets tangled up with blood cells to produce a blood clotfibrinogena soluble protein in blood plasmafood chaina chart showing the flow of energy (food) from one organism to the next, beginning with a producer (e.g. mahogany tree caterpillar song bird hawk)food weba network of interconnected food chains showing the energy flow through part of an ecosystemfossil fuelsfuels such as coal, oil and gas formed from remains of living things that existed millions of years agogall bladderbile is stored in the gall bladdergametesmale or female germ cell (a sperm or egg)gastric juicefluid that mixes with food in the stomachgenesA length of DNA that is the unit of heredity and contains codes for a specific protein. A gene may be copied and passed on to the next generation.genetic engineeringtaking a gene from one species and putting it into another speciesgenotypesgenetic makeup of an organism in terms of the alleles present (e.g. Tt or GG) geotropisma response in which a plant grows towards or away from gravityglucagonhormone that increases blood glucose concentrationglucosea type of sugarglycogena polysaccharide, used as an energy storegrowtha permanent increase in size and dry mass, by an increase in cell number or cell size, or bothguard cellsin a leaf, the guard cells change shape to open or close the stomatahaemoglobina protein in blood, responsible for carrying oxygenhaploid nucleusa nucleus containing a single set of unpaired chromosomes (e.g. sperm and egg)herbivorean animal that gets its energy by eating plantshermaphroditehaving both male and female characteristicsheterozygoushaving two different alleles of a particular gene (e.g. Tt or Gg), not pure-breedinghomeostasisthe maintenance of a constant internal environmenthomozygousHaving two identical alleles of a particular gene (e.g. TT or gg). Two identical homozygous individuals that breed together will be pure-breeding.hormonesa chemical substance, produced by a gland, carried by the blood, which alters the activity of one or more specific target organs and is then destroyed by the liverhyphaethreads making up the main body of a fungusileumlatter part of the small intestineimmunosuppressant drugssubstance taken into the body that modifies or affects chemical reactions in the bodyincisorsbiting teethingestiontaking substances (e.g. food, drink) into the body through the mouthinheritancethe transmission of genetic information from generation to generationinorganicsubstances that do not derive from living thingsinsulinhormone that helps reduce a high blood glucose levelintercostal musclesmuscles between the ribsiriscoloured part of the eye that changes shape to control amount of light entering the eyekidney tubulestiny tubes in the kidney that play a role in filtering the bloodkwashiorkorcondition caused by lack of protein in the dietlactaseenzyme that breaks down lactoselactic acida waste product of anaerobic respirationlactosea type of sugarlarge intestinepart of the intestine where remaining water and inorganic ions pass into the bloodlimiting factorsomething present in the environment in such short supply that it restricts life processeslipasesenzymes that break down fatslipidsan alternative name for fatslumenspace in the veins through which blood flowslymphtissue fluid in the lymphatic capillarieslymphocyteswhite blood cells that kill pathogensmalariadisease caused by a parasite carried by mosquitoesmaltaseenzyme that breaks down maltosemaltosea type of sugarmeiosisreduction division in which the chromosome number is halved from diploid to haploid menstrual cycleprocess of menstruation and ovulationmenstruationdischarge of blood from the lining of the uterusmesophyllinner tissue of a leafmetabolic reactionschemical reactions that take place in cellsmicropylesmall opening in the surface of an ovulemitosisnuclear division giving rise to genetically identical cells in which the chromosome number is maintained by the exact duplication of chromosomesmolarsgrinding teethmutationa change in a gene or chromosomemyceliumthe main body of a fungusmyriapodan arthropod with many legsnarcoticaddictive drugnerve cellcell that carries electrical signalsneuronealternative name for a nerve cellnicotineaddictive drug found in tobacconitrifying bacteriabacteria that change proteins in organic material into ammonia and nitratesnitrogen-fixing bacteriabacteria that change nitrogen from the air into ammonianucleuspart of a cell that contains genetic materialnutritiontaking in of nutrients that are organic substances and mineral ions, containing raw materials or energy for growth and tissue repair, absorbing and assimilating themobesitycondition of being severely overweightoesophagustube connecting mouth and stomachoestrogenhormone that controls development of female characteristicsoptic nervenerve connecting retina to brainorgana structure made up of a group of tissues working together to perform specific functionsorgan systemsa group of organs with related functions, working together to perform body functionsorganicderived from living thingsosmosisthe diffusion of water molecules from a region of their higher concentration (dilute solution) to a region of their lower concentration (concentrated solution), through a partially permeable membraneovarythe organ in which eggs (ova) are producedoviducttube through which an egg leaves the ovaryovulationprocess by which an egg is released from the ovaryovulespart of the ovary of a plant; becomes the seed after fertilisationoxygen debtcondition after exercise during which extra oxygen is needed to break down lactic acidoxyhaemoglobinmolecule formed when haemoglobin combines with oxygenpalisade cellscells near the surface of a leaf where most of the photosynthesis takes placepancreasgland containing pancreatic juicepancreatic juicefluid containing enzymes that help digestionpartially permeableallowing some substances through, but not otherspathogena harmful organismpectinaseenzyme that helps to break down cell walls in fruitpenicillinan antibioticpepsina protein-digesting enzymeperistalsisprocess by which muscles in the wall of the intestine cause food to be pushed alongphagocyteswhite blood cells that surround and digest harmful bacteriaphenotypethe physical or other features of an organism due to both its genotype and its environment (e.g. tall plant or green seed)phloem tubestubes that transport sugars around a plantphotosynthesisthe fundamental process by which plants manufacture carbohydrates from raw materials using energy from lightphototropisma response in which a plant grows towards or away from the direction from which light is comingplacentaorgan in the uterus that provides nutrients for the fetusplasmawatery constituent of blood that contains many dissolved substancesplasmolysedcondition when the surface membrane of a plant cell is pulled away from the cell wallpollinationthe transfer of pollen grains from the male part of the plant (anther of stamen) to the female part of the plant (stigma)populationa group of organisms of one species, living in the same area at the same timeprimary consumeran animal that eats plantsproducersan organism that makes its own organic nutrients, usually using energy from sunlight, through photosynthesisproteasean enzyme that breaks down proteinproteinmolecules made up of amino acidspulmonary arteryblood vessel from the heart to the lungspulmonary veinblood vessel from the lungs to the heartrecessivean allele that is only expressed when there is no dominant allele of the gene present (e.g. t or g)reflex actionaction that does not involve conscious thought (e.g. blinking)reflex arcpathway from receptor to musclereproductionthe processes that make more of the same kind of organismrespirationthe chemical reactions that break down nutrient molecules in living cells to release energyretinalight-sensitive part of the eyerodslight-sensitive cells in the retina, responsible for monochrome vision in poor lightroot hair cellsspecialised cells that help anchor a plant and absorb water and minerals from the soilsecondary consumeran animal that eats other animalssense organsgroups of receptor cells responding to specific stimuli: light, sound, touch, temperature and chemicalssensitivitythe ability to detect or sense changes in the environment (stimuli) and to make responsessexual reproductionthe process involving the fusion of haploid nuclei to form adiploid zygote and the production of genetically dissimilar offspringsickle cell anaemiaa condition causing abnormal haemoglobin, but which appears to give protection against malariasmall intestinepart of the alimentary canal between the stomach and the large intestinespermthe male sex cellspongy mesophyll (layer)inner layer of a leaf, having air spaces between the cellsstomatagaps in the