Biology Design and Communication Graphics
The marking scheme is a guide to awarding marks to candidates‟ answers. It is a concise and summarised guide and is constructed in a way to minimise its word content. Examiners must conform to this scheme and may not allow marks for answering outside this scheme. The scheme contains key words or phrases for which candidates may be awarded marks. This does not preclude synonyms or phrases which convey the same meaning as the answer in the marking scheme. Although synonyms are generally acceptable, there may be instances where the scheme demands an exact scientific term and will not accept equivalent non-scientific or colloquial terms. The descriptions, methods and definitions in the scheme are not exhaustive and alternative valid answers are acceptable. If it comes to the attention of the Examiner that a candidate has presented a valid answer and there is no provision in the scheme for accepting this answer, then he/ she must first consult with his/ her Advising Examiner before awarding marks. In general, if in doubt about any answer, examiners should consult their Advising Examiner before awarding marks. A key word may be awarded marks, only if it is presented in the correct context. e.g. Question: Briefly outline how water from the soil reaches the leaf. Marking scheme - concentration gradient/ root hair/ osmosis/ cell to cell/ root pressure/ xylem/ cohesion (or explained)/ adhesion (or capillarity or explained)/ Dixon and Joly/ transpiration or evaporation/ tension any six 6(3) Answer “ Water is drawn up the xylem by osmosis” Although the candidate has presented two key terms (xylem, osmosis), the statement is incorrect and the candidate can only be awarded 3 marks for referring to the movement of water through the xylem. Cancelled Answers The following is an extract from S63 Instructions to Examiners 2010 (section 7.3, p.22) “Where a candidate answers a question or part of a question once only and then cancels the answer, you should ignore the cancelling and should treat the answer as if the candidate had not cancelled it.” e.g. Question: What is pollination? Marking Scheme: transfer of pollen/ from anther/ to stigma 3(3) marks Sample Answer: transfer of pollen/ by insect/ to stigma The candidate has cancelled the answer and has not made another attempt to answer the question and may be awarded 2(3) marks. Surplus Answers In Section A, a surplus wrong answer cancels the marks awarded for a correct answer. e.g. Question: The walls of xylem vessels are reinforced with …………………… Marking Scheme: lignin 4 marks Sample answers: chitin, lignin – there is a surplus answer, which is incorrect, therefore the candidate scores 4 – 4 marks = 0. lignin – the answer, which is correct, has been cancelled, but there is no additional or surplus answer, therefore the candidate may be awarded 4 marks. lignin, chitin - there is a surplus answer, which is incorrect, but it has been cancelled and as the candidate has given more than one answer (i.e. the candidate is answering the question more than once only), the cancelling can be accepted and he / she may be awarded 4 marks.
Question: Name the four elements that are always present in protein Marking Scheme; carbon / hydrogen / oxygen / nitrogen 4(3) Sample answers: carbon / hydrogen / oxygen / nitrogen / calcium – there is a surplus answer, which is incorrect, and which cancels one of the correct answers, therefore the candidate is awarded 3(3) marks. carbon / hydrogen / oxygen / calcium – there is no surplus answer, there are three correct answers, therefore the candidate is awarded 3(3) marks. carbon / hydrogen / oxygen / calcium / aluminium – there is a surplus answer, which is incorrect, and which cancels one of the three correct...