AQA Bio June 2013

GCSE

SCIENCE A / BIOLOGY BL1FP Report on the Examination

4405 / 4401 June 2013

Version: 1.0

Further copies of this Report are available from aqa.org.uk Copyright 2013 AQA and its licensors. All rights reserved. AQA retains the copyright on all its publications. However, registered schools/colleges for AQA are permitted to copy material from this booklet for their own internal use, with the following important exception: AQA cannot give permission to schools/colleges to photocopy any material that is acknowledged to a third party even for internal use within the centre.

REPORT ON THE EXAMINATION GCSE SCIENCE A / BIOLOGY BL1FP JUNE 2013

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General

There was evidence that a minority of students had been entered for the Foundation tier exam,

when they may have benefitted from taking the Higher tier paper. Marks well above 45 out of 60

indicate a good depth of factual knowledge and a strength of understanding and application such

that these students may have achieved higher grades by taking the Higher tier exam.

Students should continually be encouraged to arrive at the exam properly equipped; the lack of the

correct writing equipment (a black ball-point pen or black ink and a pencil) or the lack of a

calculator may have possible consequences on performance. The quality of writing and legibility of

scanned scripts compromises students work and possibly affects the outcome of their efforts. Students often disadvantaged themselves by poor exam practice. Squashing answers into tiny

spaces, possibly after crossing out part or all of their initial answers makes reading them much

more difficult. Writing answers in the margins, which are labelled with the instruction Do not write outside the box, means that parts of answers may not be scanned and are irrecoverable. Students should also be advised not to write extensions to answers around other parts of the page,

on spare bits of white paper as these may not be seen.

Students are encouraged to read all the information in questions, as this contains guidance on the

answers required, and to pay particular attention to command words. As stated in every previous

report, describe and explain have entirely different meanings. Mixing these up throughout the paper can have significant consequences on the final mark, having a significant bearing on a

considerable number of the marks available.

Question 1 (Low Demand) (a) (i) A very large proportion of students correctly linked all three environmental changes to

the appropriate sense organ. (a) (ii) The majority of students correctly chose receptor cells. Gland cells was the most

frequently selected distracter. (b) Examiners were looking for the idea that the sugar was being used as a source of

energy. Many answers fell short of this and only referred to energy use. A surprisingly high proportion of students was confused and gave ideas about sugar being lost in sweat.

(c) (i) Many students knew the effect of the steroids, increasing the growth of muscles but

increasing heart rate proved to be a commonly chosen distracter by those less confident students.

(c) (ii) Some creditworthy answers about the possible risks to health and the side effects of

anabolic steroids were seen. However, much more commonly, students gained credit for ideas about steroids giving an unfair advantage or being considered as cheating.

Question 2 (Low Demand) (a) Many creditworthy descriptions of how the gecko resembled a leaf were seen and were

awarded the first marking point. Often these answers went on to gain the second mark by pointing out that predators would be less likely to see the gecko. Credit could not be given for simply repeating that the gecko avoided being eaten by the predators, as this was given in the stem of the question. Many students gained a mark for camouflage,


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spelt in a variety of ways. This mark was given as an alternative to either of the other two marking points. Examiners noted the number of responses that suggested the gecko changed its colour, rather like a chameleon and although this is incorrect, this was ignored as students are not expected to know this particular example.

(b) (i) A link between the thorns and the predator getting hurt was required. Students who did

not manage to gain this mark often mentioned the thorns without the idea of getting hurt. Being frightened by the thorns was insufficient for this marking point, an idea provided by a number of students.

(b) (ii) Many answers about the biting effect of the ants were seen and gained credit. There

were a number of answers about giraffes being herbivores and so would not eat the ants and these were ignored. Answers about ants carrying diseases did not gain a mark.

(c) Many students correctly pointed out that the hoverfly looked like a wasp and so

predators thought it might sting. There were a few answers which gained credit for mimicry or warning colouration, but saying that the hoverfly had black and yellow stripes did not gain credit, since this was stated in the question stem. Students who referred to warning colours often did not go on to make a point about the sting. A number of students thought that the black and yellow stripes were camouflage when they are quite the opposite.

Question 3 (Low Demand) (a) (i) The maximum temperature for a school incubator, 25oC, was widely known. 10oC was

the most commonly selected distracter. (a) (ii) The growth of pathogens was generally known to be the reason for the temperature

setting. Although toxins was the most commonly chosen distracter, viruses was selected by a considerable number of students.

(b) A significant number of students chose E, incorrectly, possibly because of the no

bacteria growing label, without realising that D had a larger area with no bacteria growing or bacteria having been killed. Stating that D had fewer bacteria did not gain the second mark since the grey area around D had no bacteria in it.

(c) Most students knew that antibiotics are ineffective against viruses because the viruses

live inside cells, although many appeared to believe that viruses are not pathogens.

Question 4 (Low Demand) (a) The majority of students chose carbon dioxide as the gas which lichens are sensitive to,

and did not gain the mark, since sulfur dioxide is the correct answer. Examiners suspected that students were unfamiliar with this part of the specification and selected the gas that they were most familiar with.

(b) (i) A high proportion of students correctly selected mutation, here. Some circled the

correct answer in the box but left the answer line blank, this was accepted. However, circling an answer in the box was ignored if any answer was written on the answer line.

(b) (ii) Many good descriptions of the pale moths being (more) easily seen and so eaten by

predators or the dark moths being less easily seen and not eaten by predators were


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provided and scored two marks. Few students went on to gain the third mark for the idea that the dark moths would reproduce or that the pale moths would be less likely to do so or that genes would be passed on by the dark moths. Appropriate references to camouflage were accepted for the idea of being less easily seen. A number of students had obviously learnt the ideas about the basis of this question and applied them well. A small number of incorrect responses stated that the soot landed on the moths and made them black and some suggested Lamarckian ideas that the moths needed to change colour in response to the change in the environment.

(c) (i) Many students gained both marks, drawing a three-layered triangular pyramid and then

labelling it appropriately. One mark was available for a correctly shaped pyramid, either unlabelled or incorrectly labelled. Alternatively one mark was awarded for students who drew what examiners thought must be a pyramid of numbers but labelled it in food chain order. Some students drew what appeared to be fire triangles with the organisms at the angles.

(c) (ii) Approximately three-quarters of students knew that either material is lost in waste from

the birds or that the larvae do not eat all the leaves, although only around a quarter selected both of these. The most commonly selected incorrect alternative was that trees are much larger than moths suggesting confusion between pyramids of numbers and biomass.

Question 5 (Low Demand) (a) The calculation proved difficult for many students and very few gained two marks for the

correct answer of 8.05, 8.1 or 8. Final answers of 805 or 8 050 000 were awarded one mark as these indicated just one mathematical error. Only rarely was the working mark for 35/100 x 23 awarded if the final answer was missing or incorrect. A number of errors were caused because students did not know the number of zeros needed for 23 million.

(b) (i) Most students gained a mark for ideas about less waste going into landfill or the council

saving money from less landfill. A few answers about less cost or less effort for the council to collect the waste were also awarded this mark.

(b) (ii) The advantage to the householder was required here and reference to using the

compost in gardens, for plants or as soil / compost all gained credit. A few students thought that the householders would have to pay less council tax and the mark was again awarded. Ideas about getting rid of garden rubbish and being eco-friendly were considered to be insufficient to gain the mark, without further qualification. Hardly any students mentioned the compost providing minerals for plants.

Question 6 (Low Demand) (a) The vast majority of students knew that the reproduction was sexual, although asexual

was by no means uncommon. (b) (i) Knowledge that the information was carried by genes appeared to be very secure. (b) (ii) The distracters neurones and body cells were incorrect answers selected by roughly

equal numbers of students, rather than gametes as a means of passing information to the next generation.


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(c) (i) The advantages needed to be comparative in order to gain the marks and so those

students who simply copied statements from the table did not gain credit. One mark was awarded for a reference to more meat and a second mark for a reference to more milk being produced each day. From their answers it was clear that many students had fulfilled the specification expectation and understood the mathematical symbols used but still failed to make a comparison. The most common reasons for marks not being awarded were because the statements were not comparative or that students confused ideas about before and after the calves were born.

(c) (ii) Again answers needed to be comparative to gain credit. The idea that Jersey cows milk

contained more protein was a common creditworthy answer, though fewer students were able to supply the idea that there was less time when no milk was produced before having a calf. Students were confused about when the cows were able or unable to produce milk and many failed to qualify this idea correctly.

(d) (i) Despite the word genes being a clue at the start of the correct answer for the definition

of genetic engineering, considerable numbers of students chose the other two distracters.

(d) (ii) Most answers were vague statements such as not safe. A few students gained credit

for possible side-effects or possible long-term effects on the health of the babies. A very small number of answers gained a mark for pointing out that the milk might contain bacteria which would be harmful to the babies. Ethical and religious arguments were not relevant in this context. A common misconception was that the genetically modified human milk would still contain some cows milk.

Question 7 (Standard Demand)

Weaker students struggled to sort out the information and data in this question and this was

reflected in their marks.

(a) (i) Many answers pointed out the lower percentage of women who died, and made correct

reference to a relevant pair of data, either between wards B and A after 1840 or within Ward B before and after 1840. A number of students also provided an explanation, which was not asked for here and so was ignored in this part of the question, although there was a strong likelihood that adding an explanation here would compromise their answer to part (a)(ii).

(a) (ii) Having provided an explanation in part (a)(i), some students did not provide the same

information required for an explanation here and so could not be given credit. It is important that students understand the requirements of command words, particularly describe and explain. Some answers explained in terms of nurses when in fact it was the doctors who were not transferring the pathogens. Disease and infection were not acceptable alternatives to pathogens / bacteria / viruses / microorganisms or microbes. A significant number of students made statements to the effect that women were cleaner than men and it was clear that a number of stereotypes concerning men being doctors or women being nurses were established.

(b) The majority of students recognised that the doctors washing their hands reduced the

percentage of patients dying and often pointed out that the decrease was large. Some students confused the reduction with the nurses washing their hands. Very few answers


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went on to say that the two wards then had similar death rates or that Ward A had a further decrease. Explanations provided were not required here.

(c) Many students did not appreciate that the question was not asking for improvements

relating to general hygiene such as better cleaning in hospitals or sheets being changed frequently. Common answers were about the use of hand gels, but more specific information such as the sterilisation of equipment was required to gain a mark. Students often referred to the introduction of vaccines as one of the ideas to better our understanding of immunity and many also gave the idea that antibiotics were now in use to prevent death in modern hospitals. A few students commented that patients could be isolated if they had infectious diseases and a minority of students gained a mark for pointing out that some infectious diseases no longer existed.

Question 8 (Standard Demand) (a) (i) Surprisingly, many students thought that the control group should eat a modified diet, for

example less fat, more fat or more fruit Healthy diet was ignored but credit was given for a balanced diet. Few answers in terms of what people normally eat were seen.

(a) (ii) Some ideas about comparisons were seen and given credit. Fair tests were often

quoted but ignored by examiners. A number of students did not appear to understand the question that was being asked, possibly because they had little experience of the idea of experimental controls.

(b) (i) The unfamiliar form of the data proved confusing. Some students appeared to read the

graph from right to left, whilst others thought the three groups were gaining mass. A number of answers were in terms of individual diets rather than similar patterns and so did not gain marks.

(b) (ii) There were some clear answers although the unfamiliar format of the data proved

confusing. Some answers were in terms of weight gain, whist others believed that merely not gaining weight would be a sign of effectiveness for slimming programmes.

Question 9 (Standard Demand)

There were some good attempts at describing the carbon cycle with students correctly naming

carbon compounds required / produced in biological processes. There was some confusion around

whether carbon dioxide was entering or leaving plants and animals during photosynthesis and

respiration and it was not unusual to read of carbon rather than carbon dioxide being transferred. A common misconception was to think that carbon dioxide was released by decay rather than

being released by the respiration of the microorganisms. The role of microorganisms was generally

not well known, many students implying that they eat dead or even living plants / animals or were themselves eaten by animals.

There was evidence that many students had made a special effort with the quality of written

communication in this question. On the whole those answers which contained considerable

biological detail were well-written.


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Mark Ranges and Award of Grades Grade boundaries and cumulative percentage grades are available on the Results Statistics

page of the AQA Website.

Converting Marks into UMS marks Convert raw marks into Uniform Mark Scale (UMS) marks by using the link below.

UMS conversion calculator www.aqa.org.uk/umsconversion

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AQA Bio June 2013