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CAIE A-Level Biology A2 Paper 5 Planning Analysis and Evaluation Questions

Practise A2 Paper 5 by planning controlled investigations, processing biological data and judging whether results support hypotheses or treatment claims.

Syllabus
2028–2030
Course
Biology 9700
Level
A2

Exam points

  • Compare treatments with untreated or reference controls, keeping starting conditions comparable.
  • Calculate rates or mean rate changes from data and report the required units and precision.
  • Plot experimental data accurately, choose suitable axes and draw a best-fit curve supported by the pattern.
  • State a null hypothesis as no significant difference between the named groups or conditions.
  • Quote graph or processed-data values to summarise trends and judge support for a hypothesis or treatment claim.
  • Use sample size, controls and study conditions to qualify validity and confidence in conclusions.

Covered syllabus points

P5.1—Defining the problem and predictionP5.2—Planning experimental methodsP5.3—Assessing result quality, validity and riskP5.4—Dealing with experimental dataP5.5—Statistical tests and data types in practical contextsP5.6—Conclusions from raw and processed dataP5.7—Evaluation of investigations

Question 1

[Maximum number: 5]

The light dependent stage of photosynthesis in a suspension of isolated chloroplasts can be investigated using the Hill reaction.

Dichlorophenolindophenol (DCPIP) can be used to follow the process. DCPIP is a blue dye which turns colourless when it is reduced by accepting hydrogen and electrons.

 oxidised DCPIP → reduced DCPIP  blue → colourless \begin{array}{clc} \text { oxidised DCPIP } & \rightarrow & \text { reduced DCPIP } \\ \text { blue } & \rightarrow & \text { colourless } \end{array}

Question (a)

(a)

Explain the reasons for:
the colour standard tube A
covering the beaker containing the chloroplast-DCPIP mixture with foil.

[ 4 ]

Question (b)

(b)

Table 2.1 shows the results of the experiment.

Table 2.1

Table 2.1

[ 1 ]

Question (i)

(i)

Complete Table 2.1 by calculating the rate of the light dependent stage of photosynthesis for the orange wavelength, using the formula:

 rate =1000t where t= time in seconds. \text { rate }=\frac{1000}{t} \text { where } t=\text { time in seconds. }
[ 1 ]

Question 2

[Maximum number: 2]

Researchers measured insect biodiversity on Acacia trees in the African savannah using the following method:
- insecticide was sprayed into each tree
- this killed the insects, which fell onto a sheet below the tree
- the dead insects were collected, identified and counted.

Table 5.1 shows summary statistics for some of the trees sampled in this study. The leaf canopy area is a measure of the size of the tree and the extent of its leaf cover.

Table 5.2 shows the diversity and abundance of some different taxonomic groups of insects in the study.

Table 5.1

Table 5.1

Table 5.2

Table 5.2

Comment on the effects of sample size on the quality and accuracy of the data in Table 5.1.

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