BIOLOGY 9700/52 - Paper 5 Planning, Analysis and Evaluation - Modified Language

Oct 23, 2026

Uploaded by Hazel

Cambridge International Biology 9700/52 Paper 5 (Planning, Analysis and Evaluation), May/June 2018, modified language edition, provides exam instructions and a structured investigation question on the light-dependent stage of photosynthesis. Using DCPIP as an indicator, the task guides candidates to interpret qualitative results, justify control and variable setups, explain apparatus roles, identify independent and dependent variables, and describe a detailed method to collect data as light intensity changes. Marks and timings are specified for each part.

LanguageEnglish

CategoryExam

FormatPDF

Pages12

Reading Time30 min

AccessFree to download

Read these instructions first

Light-dependent stage and DCPIP color change

Qualitative results (a)

Why tubes 2, 3 and 4 were included (b)

Function of the thin tank of water (c)

Modified investigation and variables

Independent and dependent variables (d)(i)

Method to collect data (d)(ii)

Light intensity calculation

Using the formula for I (e)

Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level BIOLOGY 9700/52 Paper 5 Planning, Analysis and Evaluation May/June 2018 1 hour 15 minutes Candidates answer on the Question Paper. No Additional Materials are required. MODIFIED LANGUAGE READ THESE INSTRUCTIONS FIRST Write your Centre number, candidate number and name on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. Electronic calculators may be used. You may lose marks if you do not show your working or if you do not use appropriate units. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. This document consists of 11 printed pages and 1 blank page. DC (JM) 168234 © UCLES 2018 [Turn over 2 1 During the light dependent stage of photosynthesis, the photoactivation of chlorophyll and the photolysis of water releases hydrogen ions and electrons. These are added to the carrier molecule, NADP, changing it from an oxidised state to a reduced state, as shown in Fig. 1.1. 2H+ + 2e − + oxidised NADP reduced NADP Fig. 1.1 DCPIP is a blue dye. When DCPIP is reduced by hydrogen ions and electrons, it becomes colourless, as shown in Fig. 1.2. oxidised DCPIP (blue) reduced DCPIP (colourless) Fig. 1.2 A student used DCPIP to determine if the reactions in the light dependent stage had occurred ina suspension of chloroplasts. • The suspension of chloroplasts was prepared by grinding, filtering and centrifuging a sample of leaves with ice-cold extraction medium. • Four tubes containing the mixtures and covered in foil, were set up as shown in Table 1.1. Table 1.1 | tube | contents | | --- | --- | | 1 | chloroplast suspension and DCPIP | | 2 | chloroplast suspension and distilled water | | 3 | DCPIP and extraction medium | | 4 | chloroplast suspension and DCPIP | • The tubes were illuminated through a thin glass tank filled with water as shown in Fig. 1.3. thin tank of water foil tube 1 containing chloroplast suspension and DCPIP foil ~~ ~~ timer Fig. 1.3 © UCLES 2018 9700/52/M/J/18 3 • The foil was removed from tubes 1, 2 and 3. The foil was kept on tube 4. • A timer was started immediately. • After 10 minutes the colour in each tube was observed and recorded. Table 1.2 shows the student’s results. Table 1.2 | tube | contents | foil | colour after 10 minutes | | --- | --- | --- | --- | | 1 | chloroplast suspension and DCPIP | removed | green | | 2 | chloroplast suspension and distilled water | removed | green | | 3 | DCPIP and extraction medium | removed | blue | | 4 | chloroplast suspension and DCPIP | kept in place | blue | (a) State why the results in Table 1.2 are qualitative. ................................................................................................................................................... .............................................................................................................................................. [ 1] (b) Explain why tubes 2, 3 and 4 were included. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ...................................................

FAQs

Why are the results in Table 1.2 described as qualitative?

Because the observations report color states (e.g., green/blue) without measuring a numerical value for each result.

Why were tubes 2, 3 and 4 included in addition to tube 1?

They act as controls to isolate the effects of distilled water, DCPIP/extraction medium without chloroplasts, and the role of light (foil kept or removed) when testing whether the light-dependent stage occurred.

How does the student’s hypothesis change the investigation plan?

The investigation is modified to test the claim that increasing light intensity increases the rate of the light-dependent stage, requiring identification of independent/dependent variables and a data-collection method using the apparatus.

Oct 23, 2026

Uploaded by Hazel