国际奥林匹克生物竞赛试题,英文.pdf

国际奥林匹克生物竞赛试题,英文

TheInternationalBiologyOlympiad(IBO)isa

prestigiouscompetitionthatbringstogethertalented

studentsfromaroundtheworldtoshowcasetheirknowledge

andskillsinthefieldofbiology.Thecompetition

consistsofaseriesofchallengingexamsthattest

participantsunderstandingofvariousbiologicalconcepts

andtheirabilitytoapplytheminpracticalscenarios.

HereisanexampleofanIBOexamquestioninEnglish:

Question:

Theprocessofphotosynthesisisvitalforthesurvival

ofplantsandotherautotrophicorganisms.Itinvolvesthe

conversionoflightenergyintochemicalenergy,whichis

storedintheformofglucose.Discussthemainstepsand

componentsinvolvedintheprocessofphotosynthesis,

highlightingtheirsignificanceinsustaininglifeonEarth.

Answer:

Photosynthesisisacomplexprocessthatoccursinthe

chloroplastsofplantcells.Itcanbedividedintotwo

mainstages:thelight-dependentreactionsandthelight-

independentreactions(alsoknownastheCalvincycle).

Inthelight-dependentreactions,lightenergyis

absorbedbychlorophyllmoleculesinthethylakoid

membranesofthechloroplasts.Thisenergyisusedtosplit

watermoleculesintooxygen,protons(H+),andelectrons.

Theoxygenisreleasedasabyproduct,whiletheprotons

andelectronsareusedtogenerateATP(adenosine

triphosphate)andNADPH(nicotinamideadeninedinucleotide

phosphate),whichareenergy-richmolecules.

TheATPandNADPHproducedinthelight-dependent

reactionsarethenutilizedinthelight-independent

reactions.Thesereactionstakeplaceinthestromaofthe

chloroplastsandinvolvethefixationofcarbondioxide

(CO2)toproduceglucose.Thekeyenzymeinvolvedinthis

processisRuBisCO(ribulose-1,5-bisphosphate

carboxylase/oxygenase).Thecarbondioxideiscombinedwith

afive-carbonsugarmoleculecalledribulosebisphosphate

(RuBP)toformanunst