Cambridge IGCSETM BiologyAnswers to the WorkbookExam-style questions and sample answers have been written by the author.In examinations,theway marks are awarded may be different.References to assessment and/or assessment preparationsare the publisher's interpretation of the syllabus requirements and may not fully reflect theapproach of Cambridge Assessment Intemational Education.Please note:some questions may have alternative answers which may be correct but are beyond therequirements of the syllabus.They have therefore not been included.1 Characteristics and classification ofliving organismsCore1 nutrition-taking in materials for energy,growth and developmentrespiration-the chemical reactions in cells that break down nutrient molecules and releaseenergy for metabolismexcretion-the removal of waste products of metabolismsensitivity-the ability to detect and respond to changes in the internal or external environmentreproduction-making more of the same kind of organismgrowth-a permanent increase in sizemovement-an action by an organism or part of an organism causing a change of position orplaceRespiration is the chemical reactions in cells that break down nutrientmolecules and release energy for metabolism.Breathing is the process of ventilation of thelungs.3 ref.to faeces being undigested food;which has not been formed throughmetabolic processes4 (fish and amphibians)Common features-Any two from:cold blooded;have eyes;produce jelly-covered eggs(inwater);Differences:ref.to gills/lungs;fins/legs;scales/moist skin;Cambridge IGCSE Biology Workbook Third EditionHodder Stoughton Ltd 2021Cambridge IGCSE Biology Workbook answers(amphibians and reptiles)Common features-Any two from:four legs;eyes and ears;cold blooded;lungs;Differences:ref.to moist skin/scales;jelly-covered eggs/waterproof shell;(birds and mammals)Common features-Any two from:eyes and ears;wam blooded;lungs;Differences:ref.to feathers/fur;two legs/four legs;eggs with hard shell/live young;beak/nobeak (or ref.to teeth);ears/ears with pinna;no mammary glands/mammary glands5 A insect,B arachnid,C myriapod,D crustacean6Plant1a1b2a2b3a3bName of plant(Primula vulgaris)BNarcissus pseudonarcissusCDHyacinthoides non-scriptaSupplement7 a i)Any three from:multicellular;have roots/stems/leaves;ref.to seed production;ii)Any three from:(cellulose)cell wall;sap vacuole;nucleus;cytoplasm;cellmembraneb leafshape-broad;leaf veins-parallel;cotyledons-two;grouping of flower partsin threes8 protoctists,fungi,plants,bacteriaExam-style questionsCore1 Any three from:movement;excretion;nutrition(feeding);sensitivity (irritability)[3]2 a movement;sensitivity [2]b Any two from:growth;reproduction;respiration [2]Cambridge IGCSE Biology Workbook Third Edition2Hodder Stoughton Limited 2021Cambridge IGCSE Biology Workbook answers3 Sensitivity;nutrition;growth;[3]4 A-Nucella lapillus;B-Calliostoma ziziphinum,C-Patella vulgata,D-Littorina obtusata,E-Cerastoderma edule [5]Supplement5 a The DNA is made up of a sequence of bases;each species has a unique sequence ofbases in its DNA;this makes it identifiable/distinguishable from other species.[3]b reference to the study of the base sequences in the DNA of the organisms;groupsoforganisms which are closely related have base sequences which are more similarthan those which are more distantly related [2]2 Organisation of the organismCore1 a-F;b-F;c-T;d-T;e-F;f-T;g-T;h-F;i-T;j-T2 aA membrane,B cytoplasm,C cell wall,D chloroplast,E sap vacuole,F nucleusb chloroplast,cell wall,sap vacuole3 chromosome,nucleus,cell,tissue,organ,organ system,organism4 a magnification=image size/actual size5100=156 aA group of cells with similar structures;working together to perform a sharedfunction;b Animal cells and functions-Any two examples,e.g.ciliated cells-waft mucuswith dust or bacteria away from the lungs;muscle cells-can contract to causemovement;red blood cells-transport oxygen around the body;Plant cells and functions-Any two examples,e.g.root hair cells-absorb waterand mineral salts/anchor the plant into the soil;xylem cells-transport water and mineralions from roots to leaves/provide strength for the stem;palisade mesophyll cells-7 a cytoplasm:contains cell structures,site of chemical reactionsb cell membrane:prevents cell contents from escaping,controls the passage of substancesinto and out of the cellCambridge IGCSE Biology Workbook Third Edition3Hodder Stoughton Limited 2021