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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).


MainEventsofPhotosynthesis

AbsorptionofSunlightenergybychlorophyll

tocarbohydrates.

Stomata:Tinyporespresentonthesurfaceoftheleaves.

FunctionsofStomata

(i) Exchangeofgases

(ii) Loseslargeamountofwater[watervapour]duringtranspirationandhelpsinup

flowofwater

Chloroplastcontainsthegreenpigmentchlorophyllwhichhasapivotalrolein

photosynthesis.


NutritioninAnimals

NutritioninAmoeba

Amoebahasaholozoicnutrition.Thus,solidfoodparticlesareingestedwhichreactwith

enzymesandaredigested.Itisanomnivore.

(i) Amoebamovewiththehelpofpseudopodia(extensionofcellmembrane)


(ii) Foodvaculeisformed

(iii) Undigestedfoodisthrownout.

NutritioninHumanBeings:Thehumandigestivesystemcomprisesofalimentary

canalandassociateddigestiveglands.

HUMANDIGESTIVESYSTEM


HUMANDIGESTIVESYSTEM:Asshownintheflowchart,digestionbeginsfromthmouth.In

themouthitisbrokendownbysalivaryamylase.Thefoodmovestothestomachthroughthe

oesophaguswhichperformspersistaticmovement.Enzymesandvariousdigestionjuices

fromliver,gallbladderandpancreasactonthechunksfromthestomachinthesmall

intestine.Inthelargeintestine,theremainingnutrientsareabsorbedandtheleftoveris

removedfromthebodythroughtherectumandanus.


Respiration

Itisaprocessinlivingorganismsinvolvingtheproductionofenergy,typicallywiththe

intakeofoxygenandthereleaseofcarbondioxidefromtheoxidationofcomplexorganic

substances.

(i) Gaseousexchange:Intakeofoxygenfromtheatmosphereandreleaseofcarbondioxide.

(ii) BreakdownofsimplefoodinordertoreleaseenergyinsidetheCellularRespiration

BreakdownofGlucosebyvariouspathways

Respiration

HumanRespiratorySystem:Passageofairthroughtherespiratorysystem.


MechanismofBreathing

ExchangeofGasesbetweenalveolus,bloodandtissues.


TerrestrialOrganism–useatmosphericoxygenforrespiration

AquaticOrganisms–useoxygendissolvedinwater.

RespirationinPlants:Respirationinplantsissimplerthantherespirationin

animals.Gaseousexchangeoccurthrough

1. Stomatainleaves

2. Lenticelsinstems

3. Generalsurfaceoftheroots.

Transportation

1. Humanbeingslikeothermulticellularorganismneedregularsupplyoffood,oxygenetc.,

ThisfunctionisperformedbycirculatorysystemorTransportsystem.

2. Thecirculatorysysteminhumanbeingsconsistsof:


SectionviewoftheHumanHeart

DoubleCirculation:Bloodtravelstwicethroughtheheartinonecompletecycleof

thebody.

Pulmonarycirculation:bloodmovesfromthehearttothehugsandbackthe

heart.

Systemiccirculation:bloodmovesfromthehearttorestofthebodyandback

totheheart.

Lymph-ayellowishfluidthatescapesfromthebloodcapillariesintotheintercellular

spaces.Lymphflowsfromthetissuestotheheartassistingintransportationand

destroyinggerms.


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


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


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.