WJEC 2017 Online Exam Reviewresource.download.wjec.co.uk.s3.amazonaws.com/cpd... · WJEC 2017...

WJEC 2017 Online Exam Review

GCSE BIOLOGY UNIT 1 3400U10

All Candidates' performance across questions

Question Title N Mean S D Max Mark F F Attempt %1 1265 3.4 1.6 7 48.6 98.52 1275 4.3 1.8 8 53.3 99.33 1273 3.1 1.5 8 39.2 99.14 1267 3.1 2 9 34.9 98.75 1247 3.8 2.4 10 37.6 97.16 1268 3.4 2.2 12 28.5 98.87 1157 2.2 1.7 6 36.2 90.18 1236 1.5 1.3 8 18.2 96.39 1221 1.7 1.9 12 14.3 95.1

48.6 53.3

39.2 34.9

37.6 28.5

36.2 18.2

14.3

0 10 20 30 40 50 60 70 80 90 100

123456789

Facility Factor %

Que

stio

n

GCSE BIOLOGY UNIT 1 3400U10

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Usually the question number

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The number of candidates attempting that question

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The mean score is calculated by adding up the individual candidate scores and dividing by the total number of candidates. If all candidates perform well on a particular item, the mean score will be close to the maximum mark. Conversely, if candidates as a whole perform poorly on the item there will be a large difference between the mean score and the maximum mark. A simple comparison of the mean marks will identify those items that contribute significantly to the overall performance of the candidates. However, because the maximum mark may not be the same for each item, a comparison of the means provides only a partial indication of candidate performance. Equal means does not necessarily imply equal performance. For questions with different maximum marks, the facility factor should be used to compare performance.

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The standard deviation measures the spread of the data about the mean score. The larger the standard deviation is, the more dispersed (or less consistent) the candidate performances are for that item. An increase in the standard deviation points to increased diversity amongst candidates, or to a more discriminating paper, as the marks are more dispersed about the centre. By contrast a decrease in the standard deviation would suggest more homogeneity amongst the candidates, or a less discriminating paper, as candidate marks are more clustered about the centre.

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This is the maximum mark for a particular question

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The facility factor for an item expresses the mean mark as a percentage of the maximum mark (Max. Mark) and is a measure of the accessibility of the item. If the mean mark obtained by candidates is close to the maximum mark, the facility factor will be close to 100 per cent and the item would be considered to be very accessible. If on the other hand the mean mark is low when compared with the maximum score, the facility factor will be small and the item considered less accessible to candidates.

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For each item the table shows the number (N) and percentage of candidates who attempted the question. When comparing items on this measure it is important to consider the order in which the items appear on the paper. If the total time available for a paper is limited, there is the possibility of some candidates running out of time. This may result in those items towards the end of the paper having a deflated figure on this measure. If the time allocated to the paper is not considered to be a significant factor, a low percentage may indicate issues of accessibility. Where candidates have a choice of question the statistics evidence candidate preferences, but will also be influenced by the teaching policy within centres.

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The candidates refers clearly to the relative thickness of the walls of both the artery and the vein and recognises that muscle is present. The size difference of the lumen is also stated. The direction and speed of blood flow is correctly described. There is an attempt discuss pressure but this is imprecise. The answer is adequately structured and is generally coherent. Middle Band 4 marks

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Correct answer, one mark awarded

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Incorrect answer so no mark.

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One mark is awarded as the answer refers to feeding in equivalent wording.

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The question asks for a process so "glucose" does not gain credit.

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The answer refers to a way in which carbon dioxide is removed from the sea so the first mark is awarded. The reference to carbon dioxide being harmful to sea organisms is not in the context of acidification so the second mark is not given.

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Correct answer , one mark awarded

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1 mark awarded

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Total = 5 marks

7 © WJEC CBAC Ltd.

Question Marking details Marks available AO1 AO2 AO3 Total Maths Prac

6 (a) (i) Water bath (1) 1 1 1

(b) (i) 6 plots correct (2)

5 plots correct (1)

0/1/2/3/4 plots correct (0)

+/- ½ small square tolerance

Line joining all plots no extrapolation (1)

2

1

3 4

(ii) I Increase then decrease (1)

Correct reference to 40oC (1)

2

2

II Enzyme(s) involved (1)

Correct reference to increased kinetic energy/collisions (1)

2nd mark must be in context of enzymes. 2 2

(c ) (i) use lime water (1)

becomes milky/ cloudy / white(1)

1

1 2 2

(ii) Any two (x1) from: concentration/ volume/ mass of yeast (1)

{concentration/ volume} of sugar solution/ mass of sugar (1)

Timing of observations/ amount of time (1)

pH (1)

Accept volume of sugar and yeast in water for 1 mark only

NOT temperature

2 2 2

Question 6 total 2 5 5 12 4 5

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The candidate refers to the relative thickness of the walls of the artery and vein but the comments about function are imprecise. There is some unclear expression. Lower band 1 mark

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The question refers to the control of temperature, not its measurement, The required answer is a water bath. No credit here

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The point plotted for 45°C is not placed at 67 bubbles per minute and is outside the 0.5 error tolerance. One mark awarded. The line has been drawn using a ruler but it does not pass through the centre of the points plotted at 45°C and 30°C, so the mark is not awarded.

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1 mark

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Response 1 is correct but 2 is incorrect so one mark awarded.

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The answer is incorrect, so no marks are awarded.

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The answer given describes the change in the rate of respiration but does not offer an explanation. The involvement of an enzyme is not recognised and there is no reference to increased kinetic energy or collisions with increased temperature. No credit is gained.

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The pattern of increase and decrease is not stated and the significance of 40°C is not recognised, so no marks awarded.

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Total = 2 marks

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Correct answer, one mark awarded.

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No credit , the answer is incorrect.

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Equivalent wording to feeding, the required concept in the mark scheme, One mark awarded

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Correct answer , one mark awarded

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The answer states that seagrass takes in carbon dioxide, so the first mark is awarded. The reference to the harm caused to sea organisms is ambiguous and not linked precisely enough to the acidification of sea water. The second mark is not awarded.

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2 marks awarded

4 © WJEC CBAC Ltd.


3 (a) (i) Dredging/ building/ industry 1 1

(ii) B 1 1

(b) (i) D 1 1

(ii) {Removes/ uses/ converts/ takes in} CO2 / reducing acidification

(of the sea) (1)

Acid harms living things (in the sea) (1)

accept equivalent wording in correct context

Accept

provides oxygen (1)

for respiration (1)

2 2

(c) (i) X = Photosynthesis (1)

Y= Feeding (1) Accept eating/ consuming/ ingestion

2 2

(ii) starch 1 1


14

(3400U10-1)

Examineronly

© WJEC CBAC Ltd.

6. Respiration is a series of enzyme controlled reactions which release energy. The word equation for aerobic respiration is shown below.

glucose + oxygen carbon dioxide + water + energy

Bethan investigated the effects of temperature on the rate of aerobic respiration in yeast. She used the apparatus below.

sugar and yeast in water water

bubbles of carbon dioxide

Tube 1 Tube 2

Bethan carried out the investigation at a range of temperatures from 15 °C to 45 °C.

(a) Name the apparatus she could use in order to control the temperature. [1]

(3400U10-1) Turn over.

15

© WJEC CBAC Ltd.

Examineronly

(b) The table shows the results from the investigation.

Temperature(°C)

Rate of respiration (bubbles / minute)

15 19

25 50

30 64

35 80

40 84

45 67

00 10 20 30 40 50

20

40

50

30

10

60

80

70

90

100

Rate of respiration (bubbles / min)

Temperature (°C)

(i) Produce a graph of the results by: [3]

I. Plotting the values from the table.

II. Drawing a line to join your plots using a ruler.

16

(3400U10-1)

Examineronly

© WJEC CBAC Ltd.

(ii) I. Describe how the rate of respiration changes as the temperature is increased. [2]

II. Explain the reason for the change in the rate between 25 °C and 35 °C. [2]

(c) Bethan was told that she could improve her investigation by confirming that the bubbles of gas given off by the yeast actually were carbon dioxide.

(i) Name the solution she could use in tube 2 of the apparatus to test for carbon dioxide and state the positive result. [2]

(ii) State two factors which she should have kept constant in tube 1 throughout the investigation to ensure that it was a fair test. [2]

1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12

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No credit, the answer is not correct.

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The plots are correctly positioned, well within the 0.5mm tolerance. 2 marks awarded.The candidates line is drawn using a ruler and passes thorough the centre of plots.1 mark awarded

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3 marks

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Response 1 correctly refers to the volumes of solution used but response 2 is imprecise in referring to concentrations of substances. One mark awarded.

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The candidate has correctly identified the solution as lime water and also the expected positive result. Two marks awarded.

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The answer relates to an increase in the successful collisions, detail of temperature increase and context of enzymes. Two marks awarded.

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The candidate describes the pattern in the graph of increased rate of respiration and a subsequent decrease. The significance of the change at 40°C has also been stated. Two marks awarded.

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The carbon compound wanted here is starch, so this answer does not gain credit.

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The question asks for the name of a process so the answer "glucose" does not gain credit.

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This answer does not gain any credit. The question asks for an example which is not related to food.

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Incorrect answer replaced with correct response. One mark awarded

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0 marks

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Total = 3 marks

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The candidate makes clear statements about the relative thickness of the walls of the artery and vein as well as the dimensions of the lumen. These points are correctly related to different pressures and the direction of blood flow. There is no reference to valves in the veins. The answer is written coherently and is generally well sequenced but with some repetition. Higher Band 5 marks


17

© WJEC CBAC Ltd.

Examineronly

7. The diagrams show cross sections of an artery and a vein.

Compare the structure of arteries and veins and explain how they are related to their functions in the circulation of blood in the human body. [6 QER]

outer coat

lumen

wallcontaining

muscle

ARTERY VEIN

6

8 © WJEC CBAC Ltd.


7 Indicative content Arteries

Veins

• thick {muscle/ walls } • thin {muscle/walls}

• narrow lumen • large lumen

• blood away from the heart • take blood to heart

• under high pressure • under low pressure

• have valves to prevent backflow.

5-6 marks Detailed description of artery and vein (including reference to valves for 6 marks) There is a sustained line of reasoning which is coherent, relevant, substantiated and logically structured. The candidate uses appropriate scientific terminology and accurate spelling, punctuation and grammar. 3-4 marks Some detail of artery and some detail of veins There is a line of reasoning, which is partially coherent, largely relevant, supported by some evidence and with some structure. The candidate uses mainly appropriate scientific terminology and some accurate spelling, punctuation and grammar. 1-2 marks Some detail of artery or some detail of veins There is a basic line of reasoning, which is not coherent, largely irrelevant, supported by limited evidence and with very little structure. The candidate uses limited scientific terminology and inaccuracies in spelling, punctuation and grammar. 0 marks: No attempt made or no response worthy of credit.

6


6

(3400U10-1)

Examineronly

© WJEC CBAC Ltd.

3. Read the information about seagrass and use it to answer the questions.

Seagrass growing on the sea bed

Seagrass is a green plant which lives in the sea. It covers large areas of the sea bed.

Human activities such as dredging, building and industrial development can destroy seagrass. In the 1950s the loss of seagrass was 1.5 % per year but since 1990 scientists have calculated the loss to be 7 % per year.

Fisheries need sea grass. In the Mediterranean Sea, between 30 % and 40 % of the fish caught feed on seagrass and in Indonesian seas this is 60 %.

Seagrass is important in the carbon cycle, taking in carbon dioxide to produce glucose. This is converted into another carbon compound which can be stored in its large roots. Carbon dioxide makes sea water acidic which is harmful to sea organisms.

(a) Answer the following questions using only the information given.

(i) Give one reason why areas of seagrass are lost. [1]

(ii) Which of the following statements describes the rate at which seagrass has been lost since 1950? [1]

A It has been constant every year

B It has increased

C It has decreased

D It has increased in some years and decreased in others.

Answer


34

00

U1

01

07

7

© WJEC CBAC Ltd.

Examineronly

(b) Answer the following questions using only the information given.

(i) Which statement describes how much the fishing industry depends on seagrass? [1]

A Mediterranean and Indonesian fisheries depend totally on seagrass.

B Mediterranean fisheries depend on seagrass for most of their fish.

C Indonesian fisheries depend on seagrass for less than half of their fish.

D Indonesian and Mediterranean fisheries depend on seagrass for some of their fish.

Answer

(ii) Apart from providing food, explain how seagrass is helpful to other species which live in the sea. [2]

(c) Answer the following questions using the information given and your own knowledge.

(i) Complete the diagram below which shows part of the carbon cycle, by naming processes X and Y. [2]

(ii) Name the carbon compound stored in the roots of seagrass. [1]

carbon dioxide

Y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

respiration X . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

carbon compounds in fish

carbon compounds in seagrass

8

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Incorrect answer. No credit gained.

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The value in bubbles per minutes for 45°C has been plotted at 50°C instead. One mark only credited for plotting. The line is drawn clearly and accurately so one mark awarded.

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2 marks

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Neither points 1 or 2 gain credit. Reference to an "amount" of a substance is too vague to gain credit and terms such as volume or mass were required. No marks awarded.

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The candidate has given the correct observation for a positive result in the test for carbon dioxide but has not mentioned lime water. One mark only awarded.

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This answer describes the change in the rate of respiration as temperature increases but does not explain the reason for this, as asked for in the question. There is no reference to the involvement of enzymes to an increase in kinetic energy or collisions as temperature increases. 1 mark

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The pattern of an increase followed by a decrease in the rate of respiration has been described correctly, scoring one mark. The peak of activity has been given at the wrong temperature, however and the unit is not given correctly so the second mark is not given.

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Total = 5 marks

WJEC 2017 Online Exam Reviewresource.download.wjec.co.uk.s3.amazonaws.com/cpd... · WJEC 2017...

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