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DEFINITIONS-Biology                              Define the term catalyst as a substance that               (IGCSE -2011 S...
Define transpiration as evaporation of water at                 Definethe surfaces of the mesophyll cells followed by     ...
• allele as any of two or more alternative                       Define the terms:forms of a gene                         ...
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Definitions biology-igcse-biodeluna2011


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Definitions biology-igcse-biodeluna2011

Compilation of definitions taken from the 2011 Biology IGCSE Syllabus.

IES Pedro de Luna.

Published in: Education
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Definitions biology-igcse-biodeluna2011

  1. 1. DEFINITIONS-Biology Define the term catalyst as a substance that (IGCSE -2011 Syllabus) speeds up a chemical reaction and is not changed by the reactionDefine the terms:• nutrition as taking in of nutrients which are organic Define enzymes as proteins that function assubstances and mineral ions, containing raw biological catalystsmaterials or energy for growth and tissue repair,absorbing and assimilating them• excretion as removal from organisms of toxic Define nutrition as taking in of nutrientsmaterials, the waste products of metabolism which are organic substances and mineral(chemical reactions in cells including respiration) ions, containing raw materials or energyand substances in excess of requirements for growth and tissue repair, absorbing and• respiration as the chemical reactions that break assimilating themdown nutrient molecules in living cells to releaseenergy• sensitivity as the ability to detect or sense changes Define photosynthesis as the fundamentalin the environment (stimuli) and to make responses process by which plants manufacture• reproduction as the processes that make more of carbohydrates from raw materials using energythe same kind of organism from light.• growth as a permanent increase in size and drymass by an increase in cell number or cell size orboth Define the term limiting factor as something• movement as an action by an organism or part of present in the environment in such shortan organism causing a change of position or place. supply that it restricts life processes.Define the binomial system of naming Define ingestion as taking substances (e.g.species as a system in which the scientific name of an food, drink) into the body through the mouthorganism is made up of two parts showing the genusand species. Define egestion as passing out of food that has not been digested, as faeces, through the anusDefine:• tissue as a group of cells with similar Define digestion as the break-down of large,structures, working together to perform a insoluble food molecules into small, watersolubleshared function molecules using mechanical and• organ as a structure made up of a group of chemical processestissues, working together to perform specificfunctions• organ system as a group of organs withrelated functions, working together to Define absorption as movement of digestedperform body functions. food molecules through the wall of the intestine into the blood or lymphDefine diffusion as the net movement ofmolecules from a region of their higher Define assimilation as movement of digestedconcentration to a region of their lower food molecules into the cells of the body whereconcentration down a concentration gradient, they are used, becoming part of the cellsas a result of their random movement.Define active transport as movement of ions in or Define deamination as removal of theout of a cell through the cell membrane, from a nitrogencontainingregion of their lower concentration to a region of part of amino acids to form urea,their higher concentration against a concentration followed by release of energy from thegradient, using energy released during respiration. remainder of the amino acid Biology definitions (IGCSE) - IES Pedro de Luna - 1
  2. 2. Define transpiration as evaporation of water at Definethe surfaces of the mesophyll cells followed by geotropism (as aloss of water vapour from plant leaves, through response in which a plant grows towards orthe stomata away from gravity) and phototropism (as a response in which a plant grows towards or away from the direction from which light is coming)Define translocation in terms of the movementof sucrose and amino acids in phloem;• from regions of production Define homeostasis as the maintenance of a• to regions of storage OR to regions of constant internal environmentutilisation in respiration or growth Define a drug as any substance taken into the body that modifies or affects chemical reactions in the bodyDefine respiration as the chemical reactions thatbreak down nutrient molecules in living cells torelease energy Define asexual reproduction as the process resulting in the production of genetically identical offspring from one parentDefine aerobic respiration as the release of arelatively large amount of energy in cells by thebreakdown of food substances in the presenceof oxygen Define sexual reproduction as the process involving the fusion of haploid nuclei to form a diploid zygote and the production of genetically dissimilar offspringDefine anaerobic respiration as the releaseof a relatively small amount of energy by thebreakdown of food substances in the absence ofoxygen Define pollination as the transfer of pollen grains from the male part of the plant (anther of stamen) to the female part of the plantDefine excretion as the removal from (stigma)organisms of toxic materials, the wasteproducts of metabolism (chemical reactions incells including respiration) and substances inexcess of requirements. Substances should Define growth in terms of a permanentinclude carbon dioxide, urea and salts increase in size and dry mass by an increase in cell number or cell size or both Define development in terms of increase inDefine sense organs as groups of receptor cells complexityresponding to specific stimuli: light, sound,touch, temperature and chemicals Define inheritance as the transmission of genetic information from generation to generationDefine a hormone as a chemical substance, Define the terms:produced by a gland, carried by the blood, which • chromosome as a thread of DNA, made upalters the activity of one or more specific target of a string of genesorgans and is then destroyed by the liver • gene as a length of DNA that is the unit of heredity and codes for a specific protein. A gene may be copied and passed on to the next generation Biology definitions (IGCSE) - IES Pedro de Luna - 2
  3. 3. • allele as any of two or more alternative Define the terms:forms of a gene • food chain as a chart showing the flow of• haploid nucleus as a nucleus containing a energy (food) from one organism to the nextsingle set of unpaired chromosomes (e.g. beginning with a producer (e.g. mahoganysperm and egg) tree → caterpillar → song bird → hawk)• diploid nucleus as a nucleus containing • food web as a network of interconnectedtwo sets of chromosomes (e.g. in body food chains showing the energy flow throughcells) part of an ecosystem • producer as an organism that makes its own organic nutrients, usually using energy from sunlight, through photosynthesis • consumer as an organism that gets its energy by feeding on other organismsDefine mitosis as nuclear division giving rise • herbivore as an animal that gets its energyto genetically identical cells in which the by eating plantschromosome number is maintained by the • carnivore as an animal that gets its energy byexact duplication of chromosomes eating other animals • decomposer as an organism that gets itsDefine meiosis as reduction division in which energy from dead or waste organic matterthe chromosome number is halved from • ecosystem as a unit containing all of thediploid to haploid organisms and their environment, interacting together, in a given area e.g. decomposing log or a lake • trophic level as the position of an organismDefine the terms: in a food chain, food web or pyramid of• genotype as genetic makeup of an biomass, numbers or energyorganism in terms of the alleles present(e.g. Tt or GG)• phenotype as the physical or otherfeatures of an organism due to both its Define population as a group of organisms ofgenotype and its environment (e.g. tall one species, living in the same area at the sameplant or green seed) time• homozygous as having two identical allelesof a particular gene (e.g. TT or gg). Twoidentical homozygous individuals thatbreed together will be pure-breeding• heterozygous as having two differentalleles of a particular gene (e.g. Tt or Gg),not pure-breeding• dominant as an allele that is expressed if itis present (e.g. T or G)• recessive as an allele that is onlyexpressed when there is no dominant http://biodeluna.wordpress.comallele of the gene present (e.g. t or g)Define natural selection as the greater chanceof passing on of genes by the best adaptedorganismsDefine genetic engineering as taking a genefrom one species and putting it into anotherspecies Biology definitions (IGCSE) - IES Pedro de Luna - 3