Biology 0610/52 May/June 2020: question paper and mark scheme
Cambridge IGCSE Biology (0610), Paper 5 Practical Test, May/June 2020. Read both free below, or download them. Done the paper? Get it marked by AI against this mark scheme.
You are going to investigate the effect of temperature on diffusion. Dialysis tubing is used to represent a cell membrane. Cell membranes are partially permeable.
Read all of the instructions but DO NOT CARRY THEM OUT until you have drawn a table for your results in the space provided in 1(a)(i).
You should wear the gloves and eye protection provided during the practical work.
Step 1 Label one test-tube C and the other test-tube H. Draw a small X on the outside of both test-tubes approximately half-way down each test-tube as shown in Fig. 1.1.
C H
X X
Fig. 1.1
Step 2 You are provided with two lengths of dialysis tubing which have been knotted at one end to form a bag. The bags can be opened by rubbing the unknotted end between two fingers.
Step 3 Use a pipette to put starch suspension into one of the opened dialysis tubing bags. Keep adding the starch suspension until the dialysis tubing bag is approximately three-quarters full.
Step 4 It is important that the starch suspension does not spill onto the outside of the dialysis tubing bag. Fill a 10 cm3 syringe with distilled water. Hold the dialysis tubing bag containing starch over the container labelled waste and use the syringe to carefully wash the outside of the bag with the distilled water.
Step 5 Place the dialysis tubing bag containing starch suspension into test-tube C. Fold the open end of the dialysis tubing over the top of the test-tube. Secure with an elastic band approximately 2 cm from the top of the test-tube as shown in Fig. 1.2.
Place test-tube C in the test-tube rack.
open end of the dialysis tubing bag folded over the
2 cm C top of the test-tube
elastic band
X dialysis tubing bag containing starch suspension test-tube
Fig. 1.2
Step 6 Open the other dialysis tubing bag. Repeat steps 3, 4 and 5 with the other dialysis tubing bag and test-tube H.
Step 7 Add distilled water to test-tube C until it reaches the level of the elastic band.
Step 8 Raise your hand when you are ready for hot water. Add hot water to test-tube H until it reaches the level of the elastic band.
Step 9 Measure the temperature of the water in test-tube C and test-tube H, record this in your table in 1(a)(i).
Step 10 Use a syringe to add 1 cm3 of iodine solution to the water in each test-tube.
Step 11 Start the stop-clock.
Step 12 Observe the crosses on the test-tubes by looking through the dialysis tubing as shown in
Fig. 1.3.
X drawn on the opposite side of the test-tube
eye looking at X through the dialysis tubing bag
Fig. 1.3
Step 13 Measure the time taken for each cross to stop being visible through the dialysis tubing bag. Record the times, in seconds, in your table in 1(a)(i). If the cross is still visible after
10 minutes stop timing and record the time as >600.
(a) (i) Prepare a table to record your results.
[4]
(ii) State a conclusion for this investigation.
…… [1]
(iii) Identify the variable that you have changed (independent variable) in this investigation.
…… [1]
(iv) Dialysis tubing allows small molecules to move through it by diffusion.
Starch is unable to diffuse out of the dialysis tubing bag.
State one piece of evidence for this from your investigation.
…… [1]
(v) Identify one possible source of error in this investigation and suggest one additional piece of apparatus that could be used to reduce the effect of this error.
error ……
apparatus ……
[2]
(b) (i) Amylase is an enzyme that breaks down starch to form reducing sugars.
Describe how you could test for the presence of reducing sugars.
Include the result of a positive test.
method ……
result ……
[3]
(ii) Plan an investigation to determine the effect of different concentrations of amylase on the breakdown of starch.
…… [6]
[Total: 18]
Mark scheme
1(a)(i) table drawn with minimum of two columns and a header row ; 4
column headings with units: temperature / oC and time taken / s ;
recording of two times and two temperatures ;
H takes less time than C ;
1(a)(ii) at higher temperatures, the iodine solution diffuses faster / the cross disappears more quickly / AW ; ora 1
1(a)(iii) temperature ; 1
1(a)(iv) the blue-black colour was only present inside the dialysis tubing / the water stayed brown / AW ; 1
1(a)(v) error must match apparatus: 2
error
temperature of the water not controlled / temperature changes AW ;
apparatus
thermostatically controlled water-bath / insulation / Bunsen burner ;
OR
error
difficult to tell when the cross had disappeared ;
apparatus
compare with a colour standard / compare with one that had already changed colour / colorimeter ;
OR
error
volume of starch not measured ;
apparatus
measuring cylinder / burette / pipette ;
1(b)(i) method: 3
add Benedict’s, solution / reagent ;
heat ;
result: red / orange / yellow / green ;
1(b)(ii) method: 6
1&2 use of Benedict’s reagent to measure reducing sugar produced, at set time / at regular intervals ;
ref. to use of hot water-bath / use of (thermostatically controlled) water-bath to maintain temperatures ;
OR
use of iodine solution to determine starch remaining ;
ref. to drops on spotting tile at regular intervals ;
independent variable:
3 ref. to using at least 2 different concentrations of amylase ;
variables kept constant - two from mp 4-8:
4 same type of enzyme (amylase) ;
5 concentration of starch suspension ;
6 temperature ;
7 same pH ;
8 incubating enzymes and starch suspension for same time ;
dependent variable:
9 concentration of reducing sugar produced / time taken for drops and iodine solution to remain brown ;
10 ref. to at least two further replications / repeat investigation two more times ;
11 ref. to relevant safety precaution ;
A student investigated the effect of different concentrations of sugar solution on osmosis in potato sticks.
The student used this method:
• cut six potato sticks
• measure the initial mass of each potato stick
• place each potato stick in a different concentration of sugar solution
• leave the potato sticks in the sugar solutions for one hour
• after one hour remove the potato sticks and measure the final mass of each potato stick.
(a) (i) All of the potato sticks were left in the sugar solutions for the same length of time.
State two other variables that the student should have kept constant during their investigation.
1 ……
2 ……
[2]
(ii) Identify the variable that was measured (dependent variable) in this investigation.
…… [1]
(b) The results of the investigation are shown in Table 2.1.
Table 2.1
concentration of initial mass of final mass of percentage sugar solution potato stick / g potato stick / g change in mass
/ mol per dm3
0.0 2.14 2.18 1.87
0.2 1.90 1.91 0.53
0.4 2.32 2.30 –0.86
0.6 2.25 2.21 –1.78
0.8 2.08 2.03
1.0 2.16 2.10 –2.78
(i) Calculate the percentage change in mass for the potato stick that was placed in the
0.8 mol per dm3 sugar solution.
Give your answer to two decimal places.
Space for working.
…… %
[2]
(ii) Plot a line graph on the grid to show the data in Table 2.1. One axis has been started for you.
0
[4]
(iii) State the concentration of the sugar solution at which your graph shows there would be no change in the mass of the potato stick.
…… mol per dm3 [1]
(iv) The student wanted to obtain a more accurate value for the concentration of the sugar solution at which there would be no change in the mass of the potato stick.
Suggest further investigative work that the student should carry out.
…… [2]
(c) Fig. 2.1 is a photomicrograph showing cells from a potato.
The structures visible within the cells are starch grains.
X
P
starch grain
Q
Fig. 2.1
(i) Draw a large diagram of the cell labelled X. Do not label your diagram.
[4]
(ii) Measure the length of line PQ on Fig. 2.1. Include the unit.
length of line PQ ……
The actual length of the potato cell at line PQ is 0.14 mm.
Calculate the magnification of the potato cell using the formula and your measurement.
length of line PQ magnification = actual length of the potato cell
Give your answer to the nearest whole number.
Space for working.
[3]
(iii) A student measured the actual lengths of five of the starch grains present in one potato cell. The results are shown in Table 2.2.
Table 2.2
length of starch grain / mm
0.052
0.048
0.025
0.023
0.017
Calculate the average length of the starch grains.
…… mm [1]
(d) Potato cells release carbon dioxide during respiration.
State the name of an indicator which could be used to test for the presence of carbon dioxide and give the result of a positive test.
indicator ……
result ……
[2]
[Total: 22]
Mark scheme
2(a)(i) any two from: 2
temperature ;
length / size / shape / surface area (of potato stick) ;
volume of sugar solution ;
variety of potato ;
2(a)(ii) (initial / final) mass ; 1
2(b)(i) –2.40 ;; 2
2(b)(ii) axes correctly labelled with units as: concentration of sugar solution / mol per dm3 and percentage change in mass ; 4
scale evenly spaced with suitable positive and negative scale and occupies at least half the grid ;
five correct plots ± half a small square ;
line joining all the plotted points / suitable line of best fit ;
2(b)(iii) value that corresponds with the intersection at 0% change on the candidate’s graph ; 1
2(b)(iv) use concentrations at smaller intervals ; 2
between 0.2 and, 0.3 / 0.4 (mol per dm3) ;
2(c)(i) outline: has clear single lines without shading ; 4
size: occupies at least half the space available ;
details ;; e.g. 7–9 starch grains drawn / relative sizes of starch grains / pentagon-shaped cell
2(c)(ii) (length of PQ) 45 ± 1 mm ; 3
(x)321 / 314 / 328 / 329 ;;
2(c)(iii) 0.033 (mm) ; 1
2(d) hydrogencarbonate ; 2
yellow colour ;
OR
limewater ;
becomes, cloudy / milky ;
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Where can I find the 0610/52 May/June 2020 mark scheme?+
On this page, free: the mark scheme for IGCSE Biology 0610/52, May/June 2020 (0610_s20_ms_52), and the question paper (0610_s20_qp_52), to read or download, with each question's marking points written out underneath.
How many marks is 0610/52 out of?+
Biology 0610/52 for May/June 2020 is out of 40 marks, with 1 hour 15 minutes to answer it, across 2 questions.
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