GCSE EXAMINERS' REPORTS

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1 GCSE EXAMINERS' REPORTS BIOLOGY GCSE SUMMER 2018

2 Grade boundary information for this subject is available on the WJEC public website at: Online Results Analysis WJEC provides information to examination centres via the WJEC secure website. This is restricted to centre staff only. Access is granted to centre staff by the Examinations Officer at the centre. Annual Statistical Report The annual Statistical Report (issued in the second half of the Autumn Term) gives overall outcomes of all examinations administered by WJEC. Unit Page COMPONENT 1 FOUNDATION TIER 1 COMPONENT 1 HIGHER TIER 3 COMPONENT 2 FOUNDATION TIER 6 COMPONENT 2 HIGHER TIER 8

3 BIOLOGY GCSE Summer 2018 COMPONENT 1 FOUNDATION TIER GENERAL COMMENTS A paper of over two hours in length was a considerable challenge for Foundation candidates and only those who had prepared thoroughly and undertaken revision coped well with the demands of such a long examination. With questions aimed at testing recall of factual information there was evidence that key words were known but all too often they were not used appropriately. Calculations were generally completed successfully if the task was straightforward but often more complex calculations such as manipulating percentages caused problems. With extended response there was some evidence of relevant specification content being known but many candidates had difficulty in applying their knowledge to answer questions set in novel contexts. All candidates would be well advised to re-read answers to avoid unnecessary errors and for some, poor handwriting may well have led to valuable marks being lost. QUESTION SPECIFIC COMMENTS 1. Some good answers were seen for this question on microscopy. Most candidates made suitable drawings, correctly labelled, based on a photomicrograph of cell. Many made an accurate measurement and used the given formula to calculate the magnification of the image correctly. When it came to describing a staining technique there were some sound responses based on experience of practical work, although some candidates confused named stains with other familiar chemical such as Benedict`s reagent and biuret. 2. This question on DNA revealed some lack of knowledge of facts relating to structure. Only a very small number could identify a nucleotide correctly and the letter names of bases where frequently wrongly placed. The majority of candidates, however, responded very well to the section on species identification using DNA barcoding and this was also the case with the genetics problem which followed. Some candidates unfortunately last marks in identifying the probability of the outcome of a cross because they failed to read the question properly. 3. When asked to produce a word equation for photosynthesis, it was evident that the correct chemical substances were know but frequently they were not written in the correct order and marks were lost. Graph reading was accurate but difficulties were encountered when candidates were asked to explain the reasons for an increase in the rate of photosynthesis. 4. This produced good responses on the functions of mitosis but frequently knowledge of the process was not correctly applied in the given context of the mosquito. Many answers referred to chromosome numbers of 23 or 46 when a clear image of the relevant chromosomes had been given. It was pleasing that most responses showed that the link between mosquitos and the spread of malaria was well understood and the majority of candidates were aware of the ethical issues relating to the use of stem cells. 1

4 5. It was surprising in this question on the circulatory system, that so few answers correctly identified the aorta and pulmonary artery on a diagram. Frequent incorrect answers showed confusion with other major blood vessels suggesting lack of revision. Some good responses were seen in relation to the thickness of the ventricle walls, the function of the coronary arteries and the involvement of platelets in blood clotting was known. Most descriptions of angioplasty were too lacking in detail to score well. 6. This question on osmosis, was set in a practical context. Candidates carried out calculations and plotted graphs quite well. Where marks were lost in graph plotting it tended to be because the line was badly drawn but most were able to use the graph to identify the concentration of no net movement of water. When asked to suggest improvements to the experimental method to give greater accuracy or provide a fair test a large number of responses simply made vague general points such as do it again and did not score marks. 7. Failure to read the information in the question carefully enough was the reason for many lost marks. A frequent error here was to refer to Salmonella when the text clearly referred only to Campylobacter. Answers were often too unspecific in referring to hygiene in dealing with food and often focussed only on preventing the spread of bacteria rather than the risks of contamination by contact, the importance of killing bacteria by cooking or the need to reduce bacterial reproduction. 8. This required an extended response on an example of natural selection. There was some evidence of candidates knowing the essential scientific terms but were not able to apply them in the given context of resistance to herbicides in a species of grass. Often descriptions were not well sequenced and many candidates did not score well here. In the follow-up question about the special problems facing developing countries in the use of herbicides, most answers recognised poverty as an issue but there was little awareness of food security. 9. This was the first of the questions which also appeared on the Higher Tier paper and dealt with hormones. Most foundation candidates were able to identify endocrine glands and read the graphs on the concentration of hormones in the blood accurately, although some issues occurred in the calculation of percentages. They recognised diabetes as the cause of uncontrolled blood glucose levels and gave some relevant points in evaluating and comparing different types of hormonal contraceptives. 10. The second of the questions which also appeared on the Higher Tier paper, this was set in the context of an environmental investigation. Errors were made in calculating an estimate of the numbers of two species of plants in two fields. Often marks were lost here because of failure to read the information in the question carefully and using incorrect field areas in calculations. When asked to describe a random method for the collection of data from random quadrats almost all candidates referred to using dice, tapes or a random number generator but were unable to give detail on the use of these methods in actually placing the quadrats. There were some sound responses to the questions following a bar chart on the effect of trampling on three plant species and it was encouraging to see that the value of maintaining biodiversity was understood and appreciated. 2

5 BIOLOGY GCSE Summer 2018 COMPONENT 1 HIGHER TIER GENERAL COMMENTS This was the first year that the new Biology GCSE was being assessed and a linear course, longer papers and level 9 questions together presented new challenges to the candidates. At the lower end of the paper, there were some questions that required simple recall which were answered quite poorly. Whether this reflects the demands of a linear course or poor preparation by candidates is difficult to say. The percentage attempt was 100% apart from questions 8, 9 and 10, which was possibly as a result of the challenges stated above. Candidates need to remember to constantly refer back to the stem as they progress through a question, this is especially true for questions that extend over three or four pages, e.g. question 2. At the higher end of the paper candidates found it difficult in applying familiar ideas in unfamiliar settings, e.g. questions 8, 9 and 10. It would serve candidates well to have the opportunity to practice applying their knowledge to contemporary scientific issues that arise regularly. QUESTION SPECIFIC COMMENTS 1. (a) Generally well answered by candidates who had learnt their work. (b) Most candidates were able to suggest an appropriate treatment for diabetes. The better candidates used both graphs in a comparative manner when giving evidence to support their choice of medical condition. (c) (i) Most candidates were able to use the graph to give a correct answer. (ii) I. Most candidates gave a correct reading and a calculation of the difference. II. Many candidates still struggle when asked to calculate a percentage increase. (iii) Most candidates were able to suggest an appropriate number of days, but failed to give a coherent reason. Candidates should try and use all the information given in graphs to help them, e.g. the "concentration needed to prevent ovulation" is clearly labelled on the graph and referencing this as part of their reason would have improved coherence. (iv) The weaker candidates tended to repeat the information in the stem of the question verbatim, whereas the better candidates processed the information once again in a comparative manner. 2. (a) (i) I. Surprisingly, many candidates struggled to calculate the mean and of those that did, they lost the mark because they did not look at the results for the bugleweed as a guide to the degree of rounding up needed. II. Some candidates seemed unsure as to how to calculate this number. (ii) The candidates that looked back to the information from the stem of the question and the table were able to answer this question. 3

6 (iii) Candidates struggled in this question to apply knowledge of factors that affect plant growth in a specific context. (b) (i) Candidates who had knowledge of ecological sampling did not find this question too challenging. (ii) Most students seem to struggle when evaluating scientific methods. (c) (i) This question was well answered. (ii) This straightforward recall question posed a challenge to many. 3. (a) Candidates managed well on this part. (b) Candidates showed an understanding of anaerobic respiration leading to muscle cramp caused by lactic acid being a limitation. However, not many noted that aerobic respiration is more efficient or that it releases more ATP per glucose molecule compared to anaerobic respiration. 4. (a) Candidates most commonly lost marks on this part by failing to label the pyramid of biomass with the name of the organism and its mean biomass, including units. (b) (i) This posed a problem to many, with only a few scoring two marks. (ii) Candidates on the whole were able to calculate trophic efficiency and identify the more efficient transfer. (iii) This part was poorly answered. (c) (i) As already stated, candidates struggled once again to evaluate an experimental method. (ii) This part was well answered. 5. (a) A mixed response here. Some candidates had no problems, others however struggled with standardising units of length to calculate the magnification. (c) (i) Candidates were demonstrating an understanding of how to calculate ratios, however many found it difficult to use numbers in standard form. (ii) Most candidates did not demonstrate an understanding here of the need for specialised exchange surfaces as set out in paragraph 2.1(e) of the specification. Only a few of the better candidates were able to use the data from the table and link it to the need for a larger surface area for exchange. 6. (b) (i) Candidates struggled to explain the importance of change in stomatal size. (ii) Candidates were able to identify a factor to keep constant, but then were unable to devise a simple control experiment. (c) (i) The quality of the graphs was disappointing with not many scoring full marks. The main problems were scales that did not include an origin for both axes and the quality of the line. (ii) Many candidates found it difficult to describe a graph with a plateau. 7. (a) (i) Those with good recall managed to answer both (i) and (ii). (iii) Many candidates demonstrated a knee-jerk response to the term protein synthesis in their responses to this question rather than try and solve the problem given. Detailed answers were given to a level higher than that required by the GCSE specification, and quite often it seemed the candidates showed no clear understanding of the concepts they were trying to explain. (b) (i) Many candidates were unable to give a correct genotype; however, they were able to produce the correct alleles for the Punnett square. 4

7 8. (a) Most of the candidates were able to use the data given to draw a conclusion. However, only the better candidates were able to apply their knowledge from paragraph 6.4(b) of the specification to describe the challenges faced in ensuring and adequate level of food security. (b) (i) Not many candidates could give a clear account of the main steps required to genetically modify a plant, this may be due to golden rice being an unfamiliar example of GM to them. Candidates should be taught to apply their knowledge in unfamiliar contexts so that they can learn to transfer their learning into new situations. (ii) Not many candidates were able to give coherent objections here. 9. (a) (i) Once again, candidates struggled to apply a familiar concept, evolution by natural selection, in an unfamiliar context. A common misconception was the use of 'immunity to antibiotics' rather than 'resistance', even though the word resistance had been provided in the stem of the question. (ii) Not many candidates were able to give two possible reasons here. (b) This part was well answered. 10. (a) (i) Most candidates were able to score one or two marks here. (ii) Most candidates were able to score one or two marks here. (b) Only the better candidates were able to use the diagram and give a suggestion. (c) If this question had simply asked candidates to describe a reflex action, I'm sure many would have performed far better. However, because the reflex action was presented in a slightly different context candidates seemed to struggle. Almost all candidates were able to identify the correct response of the effector, but not many were able to link this with the light being shone in the left eye. 5

8 BIOLOGY GCSE Summer 2018 COMPONENT 2 FOUNDATION TIER GENERAL COMMENTS Section A of the paper consisted of a series of questions designed to test candidates` skills based on practical tasks undertaken during the course Section B required them to analyse data. Most demonstrated experience of practical work but only those who had carefully revised the details of techniques as well as relevant theory scored highly. As with other papers, poor handwriting led to the loss of many valuable marks. Graph reading and plotting was done with accuracy in most instances and related calculations were generally carried out competently. Answers showed an awareness of risk factors in practical procedures. QUESTION SPECIFIC COMMENTS Section A 1. Answers showed a good understanding of food tests and the chemical solutions used. The only issue here was some confusion between the use of Benedict`s reagent and the use of biuret solution. Some marks were lost because candidates failed to mention the need for boiling or heating strongly in the Benedict`s test. 2. Although most candidates dealt with the data accurately in reading the diameter of clear areas on agar plates which had been treated with antibiotics, problems did arise with the particular aseptic techniques with would be employed in applying antibiotics to the plates. Some were confused between the growth of bacteria and the killing of bacteria by the antibiotics but almost all identified a suitable temperature for incubation of the agar plates. 3. This required an extended response, a task many Foundation candidates find difficult. Many were able to describe the gross structure of the kidney and identified the main areas from a photograph of a dissection. Despite this, marks were often in the lower band because the explanations of the functions the ureter and blood vessel were poorly done. Many answers were badly organised, with loss of coherence. 4. This dealt with an investigation of lipase activity at different temperatures. The graphs were, in the main, plotted accurately, with a suitable scale and candidates used their graphs to describe a trend appropriately. They went on to calculate the change in enzyme activity which occurred when the temperature was raised. Only the higher scoring candidates, however, were able explain the reason for the increased activity in relation to more collisions between enzyme and substrate. 5. Candidates were required to design an experiment, set in the context of measuring human reaction time, at different ages in order to test a given hypothesis. The majority followed the outline plan effectively, including a suitable sample size and conditions for fair testing and most were able to use the given results data to evaluate the hypothesis. 6

9 Section B 6. The question in this section also appeared on the Higher Tier paper and was a challenge for many Foundation Tier candidates. They were required to read and analyse a considerable amount of numerical, graphical and textual data on the topic of historical information about measles and the effects of the MMR vaccination. They were able to identify trends in graphs of mortality and the numbers of children vaccinated relatively well and understood the value of herd immunity. On the other hand, problems were very evident when candidates were asked to describe the development of immunity in response to vaccination. Scientific terms such as antigen and antibody were often confused and accounts showed a poor understanding of the sequence of events. It was nevertheless pleasing to note that almost all candidates could identify that a study linking MMR vaccine to autism was based on a sample size which was too small and was subject to bias. 7

10 BIOLOGY GCSE Summer 2018 COMPONENT 2 HIGHER TIER GENERAL COMMENTS The aim of this paper was to assess candidates' ability to apply their biology in a practical context. The paper included a mix of specified practical investigations direct from the specification, scientific investigations that required candidates to apply their knowledge in a novel context and questions based on a resource booklet. QUESTION SPECIFIC COMMENTS 1. (a) (i) Candidates were able to recall a wide range of methods for the spread of communicable diseases. (ii) Candidates need to be more specific in their use of scientific language. Far too many gave responses such as, "antibiotics do not work against viruses" rather than the specific response, "antibiotics do not kill viruses". (iv) Candidates struggled to apply their knowledge here. The better candidates were able to make the link between HIV weakening the immune system and the need for mass vaccination. (b) (i)(ii) Both parts answered well (c) (i)(ii) Both parts answered well. (d) Most candidates were able to recognise that antibodies and memory cells were produced, however not many were able to recall the process of antigen recognition and clonal selection. 2. (a) Many candidates found it difficult to distinguish between a hazard and a risk. Some were also unable to suggest a suitable control measure that would have been used in class. (b) (ii) Once again, as with the graph in the Component 1 paper, quality of the line was sometimes an issue. (iii) This part was well answered and generally reflected the quality of the teaching that the candidates had received. (c) (i) Only the best candidates were able to state an improvement. Many stated that more concentrations were needed, without considering what the aim of the improvement would be, i.e. improving estimation of solute concentration. Including concentrations of <20% and >40% would be superfluous and not improve their estimation. (ii) Candidates need to recognise that improved precision refers to the measurements taken, i.e. the equipment used and why it is better. Many described the use an electronic balance to improve precision without realising the importance of stating that it should be measuring to two or more decimal places. 3. (b) (i)(ii) Both parts well answered (c) (i) Well answered. 8

11 (i) Most candidates were able to identify the independent variable. Candidates tended to lose marks by using the general term amount rather than volume/concentration. 4. (a) The quality of answer reflected whether candidates had experience of kidney dissection. (b) (i) This part was not well answered with candidates unable to link processes occurring inside the kidney with their impact on the respective blood supplies. (ii) This calculation was well answered. 5. This was a challenging question that required candidates to look for clues in the stem to enable them to identify the science required to explain the results. The weaker candidates were able to attain the lower band by describing the difference between uptake in A and B and the impact of cyanide. Those who recognised from the stem that active transport was taking place were able to progress to the higher bands 6. (a) (ii) Despite struggling to suggest an appropriate control experiment in Component 1, question 6.(b)(ii), most students were able to recognise why a control experiment is important, (b) Candidates identified the role of photosynthesis in removing carbon from the air, but very few linked decomposition with the role of microorganisms which are inhibited in acidic conditions. (c) Candidates that recognised that this part was an example of a specified practical in a novel context managed well. Eduqas GCSE Biology Report Summer 2018/mp 9

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