GCSE BIOLOGY MARKING EXERCISE ANSWERS 1 · GCSE BIOLOGY MARKING EXERCISE ANSWERS 1. 5c: 5. ... so...
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GCSE BIOLOGY MARKING EXERCISE ANSWERS 1
Transcript of GCSE BIOLOGY MARKING EXERCISE ANSWERS 1 · GCSE BIOLOGY MARKING EXERCISE ANSWERS 1. 5c: 5. ... so...
GCSE BIOLOGY MARKING EXERCISE
ANSWERS 1
5c: 5
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One of the best answers. Two groups, relaxed, for the same time, take breathing rate, mean, compare. No overt idea of a repeat but otherwise very good - clear, concise, sequenced, no irrelevance, good legibility and with sound spelling, punctuation and grammar. There is a real sense that the candidate can plan investigations with a clear objective in mind. 5 marks scored
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One of the very many who chose to answer a different question to the one that was set. The exercise is ignored but would limit even an otherwise exemplary answer to Middle Band. Four points of indicative content puts the candidate into Middle Band. There is a line of reasoning which is coherent and with some structure. There is 'some accurate spelling, punctuation and grammar', so the candidate just qualifies for 4 marks.
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The candidate makes 1 point from the indicative content, by a weak reference to the two groups but fails to make use of the information about how to measure breathing rate. The discussed then becomes very confused. 1 mark scored.
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6
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The extended response question is now set in the Low Demand section of the paper, not in Standard Demand as was previously the case. As a result, the challenge is less. In this case, a careful reading of the question and astute use of the information provided would in itself potentially put the candidate at the top of the Bottom Band (2 marks) A well written 6 mark answer would include: breathing rate two groups repeat mean/mean of means compare + 2 fair test factors. Irrelevant material limits an answer to Middle Band.
GCSE BIOLOGY MARKING EXERCISE
ANSWERS 2
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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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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
GCSE BIOLOGY MARKING EXERCISE
ANSWERS 3
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The mark for a comparative answer to (iii) has not been awarded.
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Parts (a) (i) and (ii) were answered correctly with all of the credit-worthy points mentioned. This candidate recognised that when photosynthesis is at its maximum both the use of carbon dioxide and the release of oxygen are at their maximum.
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4 marks
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The calculation in part (iv) is wrong because the candidate has mis-read the graph by giving readings for the wrong gas. The correct answer should be 49.75 but could be rounded up to 49.8 or 50. 0 marks
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All correct 2 marks
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All the available marks were awarded except for the mark for recognising that maximum carbon dioxide was used by the plants when photosynthesis was at its maximum. 3 marks
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Comparative answer = 1 mark
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Correct = 2 marks
