剑桥国际考试.pdfVIP

UNIVERSITYOFCAMBRIDGEINTERNATIONALEXAMINATIONS

GCEAdvancedSubsidiaryLevelandGCEAdvancedLevel

MARKSCHEMEfortheOctober/November2009questionpaperMARKSCHEMEfortheOctober/November2009questionpaper

fortheguidanceofteachers

9700BIOLOGY

9700/21Paper2(StructuredQuestionsAS),umrawmark60

Thismarkschemeispublishedasanaidtoteachersandcandidates,toindicatetherequirementsof

theexamination.ItshowsthebasisonwhichExaminerswereinstructedtoawardmarks.Itdoesnot

indicatethedetailsofthediscussionsthattookplaceatanExaminers’meetingbeforemarkingbegan,

whichwouldhaveconsideredtheacceptabilityofalternativeanswers.

Markschemesmustbereadinconjunctionwiththequestionpapersandthereportonthe

examination.

•CIEwillnotenterintodiscussionsorcorrespondenceinconnectionwiththesemarkschemes.

CIEispublishingthemarkschemesfortheOctober/November2009questionpapersformostIGCSE,

GCEAdvancedLevelandAdvancedSubsidiaryLevelsyllabusesandsomeOrdinaryLevel

syllabuses.

Page2MarkScheme:Teachers’versionSyllabusPaper

GCEA/ASLEVEL–October/November2009970021

1(a)(i)circlearoundoneortwovariableregions;[1]

(ii)line(s)betweenonelightpolypeptideandoneheavypolypeptide,

line(s)betweenthetwoheavypolypeptides;

umofsixlinesineachsite[1]

(iii)1(disulfide)bondsarween,cysteine(s)/cysteineresidues;

AbetweenRgroupsS-HS-H

2cov