IGCSE Biology Past Paper PDF

 BI Cell and Organism Life All living need to able to do /...

 BI Cell and Organism Life All living need to able to do / process ( be Movemen Respiratio sensitivity - Ability detect an ก -Ability to move -make alive it >ความ respond chang Growth Excretio Nutritio Reproductio เป อ ยขอ งเส ( บอาหาร) ( โภชนากา ·Organism grow -make more Organism - Removal waste -taking in material s cell structu contai protein Ribosome An genetic material Synthes ↓ /control cal · A Support งเคราะ คลอโร cel · + * release contain cholorophy / in energy respiratio makeefoodne" ↳Cell sap Control Substance -> chemical get in/out # reactio of the cel convent number 2. 9. 5.239x 103 = 5239 + = back 5.2 body not respond 1 not optimal -> change, body reverse return condition to Optimum stimulus -> what causes a change in body CNS -> Central nervous syste work to return the conditions to norma Allow effector to respond Blood Glucose levels 6- 8 mmol/ &m 3 too much glucos - bad for Osmosis ( movement of water between Cell ( Too little glucose - glucose important for respiration ( the releases process energy needed by every living cel high glucose -> Insulin Ter - Low glucose -> Glucagon  thermoregulatio control Body Temperture Receptors skin Receptor brai the surface body hypothalamus control as blood flow the Brai thorough Warning Up Receptor sent info, how hot /col too hot -> sweat released Hair line fla sweating gland ( middle layer Skin call dermi evaporate take heat with it Body hair = evector muscle welaves lie fiat Blood vessels = muscular wall relax call vasodilatio more blood enter through capillaries  cooling down too cold -> Muscle contractions increase Hair stand on end shivering -> muscles contract automatically need from respiratio energy produce heat hair body -> goosebumps blood vessels -> muscular wall contract call vasoconstructio blood flows heat keep in body  Eye anatomy lens Accommodation = process lens changing shape Circular muscle Thislarger Smaller popil Radial muscle in is smaller 2 larger poopil Allow light reduce ligh  Detect colour in retina Come cel colour -detect green reds blue Rod cells -detect visual information without colour vision ( knight  111 Reproductio A sexual sexua fusion process resulting in the process involving of nuclei of production genetically 2 gameters identical off spring from genetically different 1 parent of word :- species: group Organisms that diploid: having 2 complet ke can reproduce to produce fertile off sets of chromosomes 46 Spring fertile = able to reproduce hapliod: Only single set of chromosome 23 Variation: Manding Mitosis Mais is -make new cell Identical - produce genetically different cclones from thier parent -not variation - 2 sets of produce genetic chomosomes have same chornosomes number have half chomosomes from - - as parent ( deploid) parents ( haploid) -I daugther cel -4 dargther cel -I , divisio -I division  Role of mitosis Meiosis · Growth reduction Divisio · repai I round & · replacemen · Asexual reproductio Genetic Diversity variatio genetic chomosome replicatio ( before homozygous hetero eygons ↓ chomosome separatio genotyp During phenotyp Monohybrid inheritance  Flower Reproductio & & -> strigma catch pollen AntherFollow - ->> Make seeds => - > Ovary fertilized egg can => Release /Product ↳ devolop into fetus F gamete + => ↓ receives peni Opening of uterus hold baby during pregnancy cell develop from egg Ovaries One c every 28 day down by Fallopian tube / ovidurt  Spermcel =male · gamat Secretes fluids seme ~ - -- transfe - sperm doof sperm to transfer semen Urethra - to vagina = =>> product make gameters. Carry urine and semen out of body Copulation and Fertilisatio Step 1: Find partne Step 2: Courting Behaviour Using several modes of communication, make impression Step 3: Having sex Fertilisation ( Internal Fertilisation) fusion of the nucleus of make gameter with a Eg producing zygote  pregnanc menstrual 4 Hormones cycle - endocrine -> (FSH) - Destrogen -CLH) - progesterone fertilized > zygote < embryo -> Foetus barrier ↓ รถ 6 Week - อ -embryo connect , fully y fro to placenta 38 - 20 Week & ง HIV >AIDS protect bab of DNA contains form made genetic in of gene genes -> specific segment of DNA that codes for protein Alleled the different form of dark blue gene eg eye, black eye XX = female hapliod diploid xy = male nucleus contains hucleus contains two sets of of chromosom asingle set chomosome S 13 pair, 46 chomosomes  variation and selectio Variation: differences between individuals of same species Continuou discontinuou ex. hight ex. blood type Only ABO have value in between no intermediate blood mutation = formed genetic change ( new alleles Natural Selectio variation within population · genetic ·production of off- Spring many for · struggle survival, competition resource · better adapted to the environment than Others ·passing alleles to next generation selective breeding ·select by humans with desirable features. crossing to produce the next generation · selection of off spring showing the desirable feature  and their environmen Organisms Sun: of principal source energy Input to biological System &gets consume Produce · & eat dead * & animal editreposer - sprimary Carnivore a eat only meat herbivore · eat only plants carbon cycl Micro -Organisms breakdown dead Organism and return mineral jons back to soil