Biology · May / June 2020 · Paper 62 · Question 2
0610
As printed in the paper
The question as text
A student investigated the effect of different concentrations of sugar solution on osmosis in potato sticks. The student used this method: • cut six potato sticks • measure the initial mass of each potato stick • place each potato stick in a different concentration of sugar solution • leave the potato sticks in the sugar solutions for one hour • after one hour remove the potato sticks and measure the final mass of each potato stick.
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2(a)(i)[2]
any two from:
temperature ;
length / size / shape / surface area (of potato stick) ;
volume of sugar solution ;
variety of potato ;
2(a)(ii)[1]
(initial / final) mass ;
2(b)(i)[2]
–2.40 ;;
2(b)(ii)[4]
axes correctly labelled with units as: concentration of sugar solution / mol per dm3 and percentage change in mass ; scale evenly spaced with suitable positive and negative scale and occupies at least half the grid ;
five correct plots ± half a small square ;
line joining all the plotted points / suitable line of best fit ;
2(b)(iii)[1]
value that corresponds with the intersection at 0% change on the candidate’s graph ;
2(b)(iv)[2]
test concentrations at smaller intervals ;
between 0.2 and, 0.3 / 0.4 (mol per dm3) ;
2(c)(i)[4]
outline: has clear single lines without shading ;
size: occupies at least half the space available ;
details ;; e.g. 7–9 starch grains drawn / relative sizes of starch grains / pentagon-shaped cell
2(c)(ii)[3]
(length of PQ) 45 ± 1 mm ;
(×) 321 / 314 / 328 /329 ;;
2(c)(iii)[1]
0.033 (mm) ;
2(d)[2]
hydrogencarbonate ;
yellow colour ;
OR
limewater ;
becomes, cloudy / milky ;
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