Biology · May / June 2026 · Paper 61 · Question 1
0610
As printed in the paper
The question as text
Cells from the root of a beet plant contain a red pigment. A student investigated the effect of surface area on the diffusion of pigment out of cylinders of beetroot tissue. The student was provided with four identical cylinders of beetroot tissue that had been cut to 4 cm in length, and a beaker of hot water at 60 wC. The student used this method: step 1 Label four test-tubes 1, 2, 4 and 8. step 2 Put one of the beetroot cylinders into test-tube 1. step 3 Put 10 cm3 of hot water into test-tube 1 and put a bung in the top of the test-tube. step 4 Start the stop-clock. Shake the test-tube for two minutes. step 5 After two minutes, stop the stop-clock. step 6 Remove and discard the beetroot cylinder from test-tube 1 so that only the liquid remains in the test-tube. step 7 Use the scalpel and ruler to cut a second beetroot cylinder into two pieces of equal length, as shown in Figure 1.1. Put both of the pieces of beetroot into test-tube 2. cut here to make two pieces of equal length Figure 1.1 step 8 Put 10 cm3 of hot water into test-tube 2 and put a bung in the top of the test-tube. step 9 Start the stop-clock. Shake test-tube 2 until the colour of the liquid in test-tube 2 is the same colour as the liquid in test-tube 1. Stop the stop-clock and record the time. step 10 Cut the third beetroot cylinder into four pieces of equal length. Put the four pieces of beetroot into test-tube 4. step 11 Repeat steps 8 and 9 with test-tube 4. step 12 Cut the fourth beetroot cylinder into eight pieces of equal length. Put the eight pieces of beetroot into test-tube 8. 4 step 13 Repeat steps 8 and 9 with test-tube 8. step 14 Measure the final temperature of the hot water in the beaker and record this measurement.
Read automatically from the paper; the printed page above is exact.
Show the answer and mark scheme
1(a)(i)[1]
46 (oC) ;
1(a)(ii)[4]
table drawn with minimum of two columns and a header line ; appropriate headings with units for time:
(number of) pieces / AW, (of beetroot) and time / s ;
recording (any) times for 2 and 4 and 8 pieces of beetroot ; all results correctly converted and recorded in seconds ;
1(a)(iii)[1]
higher / AW, the surface area, the greater the (rate of) diffusion ora ;
1(a)(iv)[2]
independent variable: surface area (of beetroot) ;
dependent variable: time (for the liquid to become the same colour as test-tube 1) ;
1(a)(v)[1]
any one from:
(use a) thermostatically-controlled water-bath ;
insulate ;
check the temperature of water / use a thermometer, and, replace the hot water / heat ;
1(a)(vi)[2]
any two from:
idea that shaking, (intensity / AW), may not be, consistent / AW ; idea that it is difficult to compare colours / (colours are) subjective ; idea that beetroot is still in some test-tubes but not in test-tube 1 ;
1(a)(vii)[1]
any one from:
cut away from, body / fingers / hand ;
cut (downwards) onto the, white tile / flat surface / hard surface ;
1(b)(i)[4]
Outline – single clear line no shading ;
Size – length at least 110 mm ;
Detail 1 – the ‘v’ shaped notch and the clear 'step’ that identifies the wide part of the leaf ;
Detail 2 - midrib as a double line that, continues into / connects with, the petiole
and at least two pairs of offset veins (not opposite)
and all veins touching the midrib ;
1(b)(ii)[3]
PQ = 61 ±1 (mm) ;
74.4 (mm) ;;
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