Biology 5090/62 — October/November 2015

Cambridge O-Level · Alternative to Practical · worked solutions for every part, with the mark scheme

questions

marks

minutes

Topics Experimental Contexts · Analysis, Conclusions and Evaluation · Planning Experiments and Investigations · Observations and Measurements · Microscopy and Biological Drawing · Use of Techniques, Apparatus and Materials

Q118MExperimental ContextsObservations and MeasurementsAnalysis, Conclusions and EvaluationPlanning Experiments and InvestigationsFree sample

Some students wanted to investigate the effect of concentrated fruit juice on potato tissue. Fruit juice contains a lot of sugar.

Five different solutions A, B, C, D, and E were prepared from concentrated fruit juice and water as shown in Table 1.1.

(a)

Complete Table 1.1 by inserting the volumes of fruit juice and water required to prepare solution B.

Table 1.1

solution	volume of fruit juice used / $\text{cm}^3$	volume of water used / $\text{cm}^3$	fruit juice concentration / %
A	0	100	0
B			25
C	50	50	50
D	75	25	75
E	100	0	100

(b)

Five pieces of fresh potato were cut to $70\text{ mm}$ in length. One piece was placed in each of the five solutions so that each piece was fully submerged. They were left for 40 minutes and then removed.

Fig. 1.1 shows the appearance of these five pieces of potato after 40 minutes.

Fig. 1.1

(i)

Measure the length of each piece of potato in Fig. 1.1 and record your measurements in Table 1.2.

Table 1.2

solution	fruit juice concentration / %	final length of potato piece / $\text{mm}$	change in length of potato piece / $\text{mm}$
A	0
B	25
C	50
D	75
E	100

(ii)

Complete the last column in Table 1.2 by recording the change in length of each piece of potato.

(iii)

Construct a graph to show the effect of fruit juice concentration on change in length of potato pieces.

Complete the labelling of the axes.

Fig. 1

(iv)

Suggest what has happened to the potato pieces in the different solutions that has resulted in their changes in length.

(c)

Suggest two improvements you could make to the method used for this investigation to improve its reliability.

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2 more questions

Q2Microscopy and Biological Drawing · Experimental Contexts · Use of Techniques, Apparatus and Materials14M
Q3Planning Experiments and Investigations · Analysis, Conclusions and Evaluation8M

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