GMSS 2018 Bio Prelim P1+2 MS

1 GEYLANG METHODIST SCHOOL (SEC) PRELIMINARY EXAM 2018 SEC 4E P BIOLOGY ANSWERS PAPER 1 1 2 3 4 5 6 7 8 9 10 A C C D B A C B A C 11 12 13 14 15 16 17 18 19 20 C C D B C A C C D C 21 22 23 24 25 26 27 28 29 30 D C D B A D D C D A 31 32 33 34 35 36 37 38 39 40 A B A C A A B D B C PAPER 2Section A 1 (a) (i) - start mass of the onions is different / not all are the same [1]; - use of percentage change in mass allows for valid / fair comparison to determine water potential of the onion [1]; (ii) 183 –175 = 8 ; 8 × 100 = –4.4 [1]; 183 (b) (i) line finished to –4.4 (ii) 44 g dm–3; with indication how value was obtained from graph [1] otherwise 0 m www.KiasuExamPaper.com 21 22 23 24 25 26 27 28 29 30 D C D B A D D C DDDDDDDDDDDDDDDDDDDDD A 31 32 33 34 35 36 37 383838388388383883838383838838383838383 393939339393939393939393939393939399393393 40 A B A C A A B DDDDDDDDDDDDDDDDDDDDDDD BBBBBBBBBBBBBBBBBBBBB CCCCCCCCCCCCCCCCCCCCCC PAPER 2 Section A 1 (a) (i) - start mass of the onions is dididididididddiddididdidddddfffffffffffereeereeeereeeeeeeeerennnnnnnnnnnnnnnnnnnntttttttttttttttttttttttttttttttttt ttttttttt//////////////////////////////////////////////////////////// ////////////////////////////// //////////////////////////nnnonononnononnonoonononononononnnnonononononnnnnononononnnonnoononnonnonononnnnononnnnnononnnnnnnnnnonononnnnnnnonnnnnnoononnnnnnnnnnnnnonnnnnnoonnnnnonnnnnoonnnnonnnonnnnnnononnnnonononnnoooonnnooononnnonooooonnnoooooooonnnoooooooonnooooooooooooooooooooooooooooooooooottttttttttttttttttttttttttttttttt tttttttt ttttttttttttt ttttttttttt t ttttttttttttttttaaaaaaaaallalalaaaaallalalllaalllllalallalalaaallalaaaalalaaaaaaaaaaaaaaaaaaaaaalaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaalalalalallaallalalllaalaallllllllllllllllllllll aareeeeeeeeeeeeeeeeeeee thhhhhhhhhhhhhhhhhhhhhheeeeeeeeeeeeeeeeeeeesamemememememememememememememememmemememmemem[[[[[[[[[[[[[[[[[[[[111111]1111111111111; - use of percentage chchchchchchchchchccchchccchchhhananannnnannnnnnnnnnnnngeggg in mammmmmmmmmmmmmmmmmssssssssssssssssssssssssssssssss allows for vaaaaaaaaaaaaaaaaaaaaalliddddddddddddddddddddddd/ fairrrrrrrrrrrrrrrrrrrrrccccccccccccccccccccccoooooomoooooooooooooooparison to determinewwwwwwwwwwwwwwwwwwatatataatttatataaerpppppppppppppppppppotototototototottottttotttteneneneneneneneneneeeeeeetititittittittttititititttial of thhhhhhhhhhhhhhhhhhe onion [1]; (ii) 183 – 1755555555555555555==============8 ;;;;;;;;;;;; 8 88 888888 8888888888 ×××××××××××××××××××10111110= – 4444.4444444 [1]] ;;;;;;;;;;;;;;;;;; 188888888888888888333333333 (b) (i)))))))))))))))) lililililililililiilillilliiiinefinnnnnnnnnnnnnnnnisssssssssssssssheheheheheheheheheeeheeeheeheddddddddddddddddtototototototototototototott – 4.444444444444444 319

2 (c) -m o v e m e n t o f w a t e r b y o s m o s i s t h r o u g h p a r t i a l l y p e r m e a b l e membrane(s) [1]; - When onion cell sap has lower water potential than sodium chloride solution / sodium chloride solution has higher water potential than onion cell sap, water enters the onion cells and causes the cells to swell and eventually gain in mass; 2 (a) (i) oesophagus [1] (ii) peristalsis [1] (b) - The presence of food in H, stomach, stimulates the gastric glands to secrete gastric juice which contains hydrochloric acid and inactive pepsinogen. Hydrochloric serves to activate pepsinogen to pepsin [1]. -T h e m u c u s a l s o s e r v e s t o p r e v e n t c o r r o s i o n b y a c i d [ 1 ] . - The walls of stomach is coated with mucus to serve as a protection / barrier which prevents damage / breakdown by pepsin [1] on the stomach walls which are made of protein [1]. - The mucus also serves as lubrication during peristalsis in the stomach [1] [max 4m] (c) (i) The heart is not involved / no connection between E and the heart [1]. (ii) There are less mucus in E [1]. Acid from stomach damages the cells / walls of E [1]. The acid is neutralised by the alkaline nature of the medication [1]. 3( a ) ( i ) Rcorpus luteum [1] S(Grafiaan) follicle [1] (ii) ovulation [1] (b) (i) oestrogen [1] (ii) progesterone [1] 4 (a) (i) control (ii) During the first four months, the heart rate decreases rapidly/ AW [1] from 85 to 62 beats per minute [use of data from Fig. 4.1 – 1m] . The heart rate remains (more or less) constant between 59 –62 beats per minute [1]. www.KiasuExamPaper.com (b) - The presence of food in H, stomach, stimulates the gastric glands to secrete gastric juice which contains hydrochloric acidaandndiinanactcive pepsinogen. Hydrochloric serves to activate pepsinogenen to pepepsin [1]. - The mucus also serves to prevent corrosion b y acacidid[[1]1]. - The walls of stomach is coated with mucus tosssserererervvvveaaaassss a prprprprototototecececectitititionononon / barrier which prevents damage / breakdowwwnnnnnnnnnnnbbybybybybybybybybybyybybybybybybybybybybyybybybyybybybybyybybybybyybybybybyybybybybybybybyyybyybybybybybyyybybybyybybybybybybybybbbbyybybybybyybybybybbybbybybbbybybybybybbybbbybybbbybyybybybyybybbbyybybbyybbyybybyyyyybyyyyyyyyyyyyyyyyyyyyyyyyypppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppeeeeepeeeeeeepepepepepepepepepepepepeeepepepepepeepepepepepeeeeeepepepepeeepeepeeeeeepepeeeeeeppeeeepeeeppepeppepeeepeepepeeeeeeeeeeeeeeeesisisisisssssssssssssn [1]]oooonttthhhe stomach walls which are made of proteiiiinnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn[1[1[1[11[1[[11[1[1[1[1[1[1[111[1[1[1[1[11111[1[11[1[111[1[11[1[1[1[1[1[1[[111[[[1[1[1[11[1[1[1[1[1[1[[1[1[1[1[1[[[1[11[[[1[[1[1[1[1[[1[[[[[[1[1[1[1[1[1[1[1[1[11111111[1[111111111[1111[111[111[11111[111[[1[[[[[[[[]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]] ......... - The mucus also serves as lubricationddddddddddddddddddddddddururururuuuuuuururururururururrruuuuururrururruruuuurrruuuuurrrrurruruuuuuuruuuuuuuururuuuuuruuuuuuuuuuuuuuruuuuurinininniiiiniiniininininninininiinininnininininnninininninninininiininininiininininnnnnninnininninninnninnnnnnninininnnnnnnnnnniiniiiinniniinnniiniiiinniiinnnnnnnnnggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggppppppppeppepepppppepepppepeepepepppppeppppppepepepepppppppppppeepepepppppppppppepeppppppppepepeepepppepepppppppeppppppeppppepepeppepppeppppprrrrirrstttaaaalsisisisissssintttthhhh e e sstomach [1] [max 4m] (c) (i) The heart is not involved / no connectioionnbetween E and the heart [1] . (ii) There are less muccusiin nEE[1].. Acid from stomachhdadamamgegs s ththe ececlllls/ walls of E [1]. The acid is neutralilisesed dbybyttheheaalkkalaine nature of the medication [1]. 3 (a) (i) R cocorppususlluteumm [1[1]] SS (( GrGrafafiaann))fofolllliciclee [1[1] (ii) ovulatatioionn [1[1]] (b) (i)) eoeststrorogegenn[1[] (ii) prprogogeseterone[1] 4 (a) (i) control 320

3 (b) line / curve starts at 36 months drops with similar gradient to line K [1]; to between 70 and 74 bpm [1]; levels to run parallel with the J and K [1]; (c) prevent constriction of muscular wall in arteries / arterioles [1]; with larger lumens / dilation / widens / AW, reduces fats deposits; OR less resistance / friction / AW to blood flow. [1] www.KiasuExamPaper.com (c) prevent constriction of muscular wall in arteries / artrtereriooles [1] ; with larger lumens / dilation / widens / AW,rredeucesffatatssdeposits; OR less resistance / frictionn/AW Wtotoblooddfflolow.w. [1[1]] 321

4 5 (a) xCross Plant 2 with a white flowered plant (test cross); [1] xIf all offspring have purple flowers, Plant 2 is homozygous; [1] xIf 50% of offspring have purple flowers and 50% of offspring have white flowers, plant 2 is heterozygous; [1] (b) Let the allele for purple flower be P, the allele for red flower be R and the allele for white flower be W. Plant 1 Plant 2 Parental phenotypes Purple + Red X Purple Parental genotypes