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CBSEClass10Science
RevisionNotes
CHAPTER–6
LIFEPROCESSES
Alllivingthingsperformcertainlifeprocesseslikegrowth,excretion,respiration,
circulationetc.
Thebasicfunctionsperformedbylivingorganismsfortheirsurvivalandbody
maintenancearecalledlifeprocess.
Basiclifeprocessesare:Nutrition,Respiration,Transportation,Excretionetc.
LifeProcessesrequireenergywhichisprovidedbynutrition.
ModesofNutrition
1. Autotrophic:-KindofnutritioninwhichorganismscansynthesizetheirownfoodEg.
GreenPlants
2. Heterotrophic:-Kindofnutritionofwhichorganismsdonotpossesstheabilityto
synthesizetheirownfood.Theydependonautotrophsfortheirfoodsupplydirectlyor
indirectly.Eg.Animals,Fungi
AutotrophicNutrition
Autotrophs:Theorganismswhichcanmaketheirownfoodarecalledautotrophs
(greenplants).
Photosynthesis:Theprocessbywhichgreenplantsmaketheirownfoodwiththe
helpofCO andH Ointhepresenceofchlorophyllandsunlightisalsocalled
photosynthesis.
RawMaterialsforPhotosynthesis:
SiteofPhotosynthesis:Chloroplastintheleaf.Chloroplastcontainchlorophyll.(green
pigment).
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MainEventsofPhotosynthesis
AbsorptionofSunlightenergybychlorophyll
tocarbohydrates.
Stomata:Tinyporespresentonthesurfaceoftheleaves.
FunctionsofStomata
(i) Exchangeofgases
(ii) Loseslargeamountofwater[watervapour]duringtranspirationandhelpsinup
flowofwater
Chloroplastcontainsthegreenpigmentchlorophyllwhichhasapivotalrolein
photosynthesis.
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NutritioninAnimals
NutritioninAmoeba
Amoebahasaholozoicnutrition.Thus,solidfoodparticlesareingestedwhichreactwith
enzymesandaredigested.Itisanomnivore.
(i) Amoebamovewiththehelpofpseudopodia(extensionofcellmembrane)
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(ii) Foodvaculeisformed
(iii) Undigestedfoodisthrownout.
NutritioninHumanBeings:Thehumandigestivesystemcomprisesofalimentary
canalandassociateddigestiveglands.
HUMANDIGESTIVESYSTEM
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HUMANDIGESTIVESYSTEM:Asshownintheflowchart,digestionbeginsfromthmouth.In
themouthitisbrokendownbysalivaryamylase.Thefoodmovestothestomachthroughthe
oesophaguswhichperformspersistaticmovement.Enzymesandvariousdigestionjuices
fromliver,gallbladderandpancreasactonthechunksfromthestomachinthesmall
intestine.Inthelargeintestine,theremainingnutrientsareabsorbedandtheleftoveris
removedfromthebodythroughtherectumandanus.
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Respiration
Itisaprocessinlivingorganismsinvolvingtheproductionofenergy,typicallywiththe
intakeofoxygenandthereleaseofcarbondioxidefromtheoxidationofcomplexorganic
substances.
(i) Gaseousexchange:Intakeofoxygenfromtheatmosphereandreleaseofcarbondioxide.
(ii) BreakdownofsimplefoodinordertoreleaseenergyinsidetheCellularRespiration
BreakdownofGlucosebyvariouspathways
Respiration
HumanRespiratorySystem:Passageofairthroughtherespiratorysystem.
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MechanismofBreathing
ExchangeofGasesbetweenalveolus,bloodandtissues.
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TerrestrialOrganism–useatmosphericoxygenforrespiration
AquaticOrganisms–useoxygendissolvedinwater.
RespirationinPlants:Respirationinplantsissimplerthantherespirationin
animals.Gaseousexchangeoccurthrough
1. Stomatainleaves
2. Lenticelsinstems
3. Generalsurfaceoftheroots.
Transportation
1. Humanbeingslikeothermulticellularorganismneedregularsupplyoffood,oxygenetc.,
ThisfunctionisperformedbycirculatorysystemorTransportsystem.
2. Thecirculatorysysteminhumanbeingsconsistsof:
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SectionviewoftheHumanHeart
DoubleCirculation:Bloodtravelstwicethroughtheheartinonecompletecycleof
thebody.
Pulmonarycirculation:bloodmovesfromthehearttothehugsandbackthe
heart.
Systemiccirculation:bloodmovesfromthehearttorestofthebodyandback
totheheart.
Lymph-ayellowishfluidthatescapesfromthebloodcapillariesintotheintercellular
spaces.Lymphflowsfromthetissuestotheheartassistingintransportationand
destroyinggerms.
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TransportationinPlants:Therearetwomainconductingtissuesinaplant.
(a) Xylem(b)Phloem.
Transpirationistheprocessbywhichplantslosewaterintheformofvapours.
RoleofTranspiration
1. AbsorptionandupwardmovementofwaterandmineralsbycreatingPULL.
2. HelpsintemperatureregulationinPlant.
Translocation:Transportoffoodfromleaves(foodfactory)todifferentpartofthe
plantiscalledTranslocation.
Excretioninhumanbeings:Theprocessoftheremovaloftheharmfulmetabolic
wastesfromthebodyiscalledexcretion.Excretorysystemofhumanbeingsincludes:
1. Apairofkidney
2. AUrinaryBladder
3. ApairofUreter
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4. AUrethera
ProcessofExcretion
Renalarterybringinbloodcontainingwastesubstancestothekidneys.
Kidneyfiltersblood.
Urineproducedinthekidneyspassesthroughtheuretersintotheurinarybladder
whereitisstoreduntilitisreleasedthroughtheurethera.
FunctionofKidney:Itisremovewasteproductfromthebloodi.e.,ureawhichis
producedintheliver.
Nephron:Eachkidneyhasalargenumberoffiltrationunitscallednephrons.
NephronisthestructuralandfunctionalunitofKidney.
MechanismofUrineFormation:TheUrineformationinvolvesthreesteps:
GlomerularFiltration:BloodisfilteredfromtheglomerulusintoBowmanCapsule
ofthenephron.Thisfiltratepassesthroughthetubulesofthenephron.
Tubularre-absorption:Now,usefulsubstancesfromthefiltrateLike ,
glucose,aminoacidsetc.arereabsorbedbythecapillariessurroundingthenephron
intotheblood.
Secretion:Urea,extrawaterandsaltsaresecretedintothetubulewhichopenup
intothecollectingduct&thenintotheureter.
Haemodialysis:Theprocessofpurifyingbloodbyanartificialkidney.Itismeantfor
Kidneyfailurepatient.
ExcretioninPlants
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1. Oxygenreleasedduringphotosynthesis.
2. bytranspiration
3. Wastesmaybestoredinleaves,barketc.whichfallofffromtheplant.
4. Wasteproductsstoredasgums,resininoldXylem
5. Plantsexcretesomewasteintothesoilaroundthem.
Whatyouhavelearnt
Movementofvarioustypescanbetakenasanindicationoflife.
Themaintenanceofliferequiresprocesseslikenutrition,respiration,transportof
materialswithinthebodyandexcretionofwasteproducts.
Autotrophicnutritioninvolvestheintakeofsimpleinorganicmaterialsfromthe
environmentandusinganexternalenergysourceliketheSuntosynthesiscomplex
high-energyorganicmaterial.
Heterotrophicnutritioninvolvestheintakeofcomplexmaterialpreparedbyother
organisms.
Inhumanbeings,thefoodeatenisbrokendownbyvariousstepsalongthe
alimentarycanalandthedigestedfoodisabsorbedinthesmallintestinetobesentto
allcellsinthebody.
Duringtheprocessofrespiration,complexorganiccompoundssuchasglucoseare
brokendowntoprovideenergyintheformofATP.ATPisusedtoprovideenergyfor
otherreactionsinthecell.
Respirationmaybeaerobicoranaerobic.Aerobicrespirationmakesmoreenergy
availabletotheorganism.
Inhumanbeings,thetransportofmaterialssuchasoxygen,carbondioxide,foodand
excretoryproductsisafunctionofthecirculatorysystem.Thecirculatorysystem
consistsoftheheart,bloodandbloodvessels.
Inhighlydifferentiatedplants,transportofwater,minerals,foodandothermaterials
isafunctionofthevasculartissuewhichconsistsofxylemandphloem.
Inhumanbeings,excretoryproductsintheformofsolublenitrogencompoundsare
removedbythenephronsinthekidneys.
Plantsuseavarietyoftechniquestogetridofwastematerial.Forexample,waste
materialmaybestoredinthecell-vacuolesorasgumandresin,removedinthe
fallingleaves,orexcretedintothesurroundingsoil.