Cambridge AssessmentInternational EducationCambridge International AS A LevelCANDIDATENAMECENTRECANDIDATENUMBERNUMBERBIOLOGY9700/52Paper 5 Planning,Analysis and EvaluationFebruary/March 20231 hour 15 minutesYou must answer on the question paper.No additional materials are needed.INSTRUCTIONS.Answer all questions.Use a black or dark blue pen.You may use an HB pencil for any diagrams or graphs.Write your name,centre number and candidate number in the boxes at the top of the page.Write your answer to each question in the space provided.Do not use an erasable pen or correction fluid.Do not write on any bar codes.You may use a calculator.You should show all your working and use appropriate unitsINFORMATION.The total mark for this paper is 30.The number of marks for each question or part question is shown in brackets ]This document has 20 pages.Any blank pages are indicated.DC(CE/SG)315536/4©UCLES2023[Turn over1 Potatoes are underground organs made by the potato plant,Solanum tuberosum.Fig.1.1 shows a potato plant.soilpotatoFig.1.1Potatoes contain high quantities of starch and are a popular food.After harvesting,potatoes arestored.During storage,the starch content of potatoes gradually decreases due to the breakdownof starch molecules into glucose.A glucose assay using a Benedict's test and a colorimeter can be used to determine theconcentration of glucose in potatoes.The glucose assay uses these steps:The outer skin is removed from a potato.The potato is cut into small pieces that are then ground into a pulp using a mortar andpestle.The potato pulp is filtered to remove most of the solids and obtain potato juice.Excess Benedict's solution is added to the potato juice.The mixture is heated in a water-bath at 90C for five minutes.During this five-minuteperiod,copper ions (Cu2+)in the Benedict's solution react with glucose in the potatojuice to form an insoluble precipitate.The mixture is filtered to remove the precipitate.The filtrate,which is blue,containscopper ions that did not react with the glucose in the potato juice while the mixture wasbeing heated.A sample of the blue filtrate is transferred to a colorimeter tube (cuvette).A colorimeter is used to measure the absorbance of the blue filtrate.A calibration curve is used to determine the glucose concentration of the potato juicefrom the measurement of absorbance.©UCLES20239700/52/F/M233Fig.1.2 shows one type of colorimeter.hole to holdPcolorimeter tubeUSE CUVETTE CAPSdigital readout ofabsorbance0000tube3 cm3 sampleto be tested(blue filtrate)Fig.1.2A clean colorimeter tube containing the sample to be tested is placed in the colorimeter.Light ispassed through the sample and the absorbance of light by the sample is measured.(a)(i)Outline how colorimeters should be prepared before carrying out measurements onsamples so that correct absorbance readings in the glucose assay are obtained.©UCLES20239700/52/F/M23