Cambridge IGCSE™ BIOLOGY 0610/62 Paper 6 Alternative to Practical March 2022 MARK SCHEME Maximum Mark: 40 Published This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge International will not enter into discussions about these mark schemes. Cambridge International is publishing the mark schemes for the March 2022 series for most Cambridge IGCSE™, Cambridge International A and AS Level components and some Cambridge O Level components. This document consists of 7 printed pages. © UCLES 2022 [Turn over repeat the investigation / AVP ; cut away from body / cut towards tile / cut on flat surface / AW ; 1(a)(vi) 1(a)(vii) © UCLES 2022 Page 5 of 7 any two from: concentration of acid ; volume of acid ; type of acid ; agar (cut from) same (block) / type of indicator ; (block) starting colour / green at the start ; 1(a)(v) outline single clear line no shading ; size larger than image ; details ;; e.g. proportion, filaments and lamellae shown, 14–8 branches, at least one alternation of branches size of the block / AW ; 1(a)(iv) 1(c)(i) time (taken for block to completely change colour) ; 1(a)(iii) 10 (:1) ; the time taken (for the agar block to change colour) increases as the, side length / diffusion distance / surface area, increases ; ora 1(a)(ii) 1(b) table drawn with a minimum of two columns and a header line ; appropriate headings with units ; recording of four readings (for time) ; correct conversion to seconds ; Answer 4 1 1 1 2 1 1 1 4 Marks Cambridge IGCSE – Mark Scheme PUBLISHED 1(a)(i) Question 0610/62 Guidance March 2022 independent variable: 1 (at least) two different temperatures ; 2 method of maintaining temperature ; 1(e) © UCLES 2022 (add) biuret (solution) ; purple / AW ; 1(d) Page 6 of 7 9 two or more replicates or repeat investigation twice ; 10 valid safety precaution ; constant variables ;; 7,8 concentration of protease / volume of protease / type of protease / type of film / pH / size of film pieces / light (intensity) / volume of buffer / consistent shaking method: 4 use of a buffer ; 5 equilibration to correct temperature ; 6 shaking ; Guidance 6 2 3 MP1 measurement of line PQ MP2 correct calculation MP3 correct rounding to three decimal places ecf MP2 and MP3 Marks Cambridge IGCSE – Mark Scheme PUBLISHED dependent variable: 3 measuring time for film, to become transparent / to become clear / for crystals to fall off ; line PQ 90±1(mm) ; 0.162 / 0.164 / 0.165 ;; Answer 1(c)(ii) Question 0610/62 March 2022 62 ;;; 2(b)(iii) © UCLES 2022 Page 7 of 7 intersection of line on graph at 20 minutes shown ; value from graph with tolerance of ± half a small square ; 2(b)(ii) add DCPIP ; (becomes) colourless ; axes labelled with units ; even scale that occupies at least half the grid in both directions ; five points plotted accurately ± half a small square ; suitable line ; 2(b)(i) 2(c) any two from: beaker / balance / Bunsen (burner) or water-bath / gauze / tripod / AVP ;; Answer Guidance 2 3 MP1 correct values selected from the table MP2 correct calculation MP3 correct rounding to two significant figures ecf MP2 and MP3 2 4 2 Marks Cambridge IGCSE – Mark Scheme PUBLISHED 2(a) Question 0610/62 March 2022