Biology · Oct / Nov 2025 · Paper 61 · Question 1
0610
As printed in the paper
The question as text
A student investigated the effect of temperature on the movement of water in celery stalks. The water contained a blue dye. In plant stems such as a celery stalk, water moves in the xylem tissue within the vascular bundles. The student used this method: Step 1 Take two stalks of celery and cut them so that they are both 10 cm long. Step 2 Prepare an ice-cold water-bath C and a warm water-bath W. Place a beaker of blue dye into each water-bath, as shown in Fig. 1.1. large beaker C containing ice-cold water large beaker W containing warm water blue dye blue dye Fig. 1.1 Step 3 Measure the temperatures of the water in water-bath C and water-bath W. Step 4 Let the blue dye equilibrate in the water-baths for three minutes. Step 5 After three minutes, place one celery stalk into each beaker of blue dye, as shown in Fig. 1.2. Keep the celery stalks in the blue dye for ten minutes. 10 cm long celery stalk not to scale water-bath blue dye Fig. 1.2 Step 6 After ten minutes, measure the final temperatures of the water in water-bath C and water-bath W.
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1(a)(i)[1]
C = 11 and W = 12 ;
1(a)(ii)[4]
table drawn with correct number of columns and a header line ;
appropriate column / row headings, with units for distance ;
recording of correct number of sections for both C and W ;
recording of correct total distances for both C and W ;
1(a)(iii)[2]
6.5 ;
mm per minute ;
1(a)(iv)[1]
the higher the temperature the greater the (rate of) dye / water movement ;
1(a)(v)[1]
to identify, anomalous results / outliers / results that do not follow the trend ;
1(b)[2]
any two from:
both used celery OR same, species / type, of plant ;
length of celery (stalk) ;
both used blue dye OR type / colour of dye ;
time to equilibrate ;
length of time in the dye ;
width of sections ;
1(c)(i)[2]
error from Table 1.1
temperature (of the water-bath) not controlled / AW ;
improvement
thermostatically controlled water–bath ;
1(c)(ii)[1]
cut smaller / thinner sections OR cut the celery vertically / longitudinally ;
1(d)[2]
0.28 (mm3) ;
1(e)(i)[3]
line AB = 60 ±1 (mm) ;
2 (mm) ;;
1(e)(ii)[3]
any three differences from:
leaf miner fly / Fig. 1.7
black aphid / Fig. 1.6 1
larger
OR
smaller
2
shorter antennae / AW
OR
longer antennae / AW 3
has wings
AND
no wings
4
hairs on body
AND
no hairs on body
5
larger eye
OR
smaller eye
6
lack of two projections
AND
two projections / AW / AW, sticking out of
sticking out of
abdomen / back
abdomen / back
7
shorter legs
OR
longer legs
8
thicker legs
OR
thinner legs
9
only three legs (visible)
AND
six legs
10
larger head
OR
smaller head
;;;
1(f)[4]
single clear outline with no shading ;
drawing larger than half the available space ;
detail 1: deep V-shaped cleft correctly located on the upper right third of the leaf ;
detail 2: between three and five separate veins coming from the same level at the top of the petiole ;
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