Edexcel a level biology paper 3 mark scheme june 2023

Mark Scheme (Results) Summer 2023 Pearson Edexcel GCE In Biology (9BIO) Paper 3: General and Practical Principles in Biology Edexcel and BTEC Qualifications Edexcel and BTEC qualifications are awarded by Pearson, the UK’s largest awarding body. We provide a wide range of qualifications including academic, vocational, occupational and specific programmes for employers. For further information visit our qualifications websites at or . Alternatively, you can get in touch with us using the details on our contact us page at Pearson: helping people progress, everywhere Pearson aspires to be the world’s leading learning company. Our aim is to help everyone progress in their lives through education. We believe in every kind of learning, for all kinds of people, wherever they are in the world. We’ve been involved in education for over 150 years, and by working across 70 countries, in 100 languages, we have built an international reputation for our commitment to high standards and raising achievement through innovation in education. Find out more about how we can help you and your students at: Summer 2023 Question Paper Log Number P71911A Publications Code 9BIO_03_2023_MS All the material in this publication is copyright © Pearson Education Ltd 2023 General Marking Guidance • All candidates must receive the same treatment. Examiners must mark the first candidate in exactly the same way as they mark the last. • Mark schemes should be applied positively. Candidates must be rewarded for what they have shown they can do rather than penalised for omissions. • Examiners should mark according to the mark scheme not according to their perception of where the grade boundaries may lie. • There is no ceiling on achievement. All marks on the mark scheme should be used appropriately. • All the marks on the mark scheme are designed to be awarded. Examiners should always award full marks if deserved, i.e. if the answer matches the mark scheme. Examiners should also be prepared to award zero marks if the candidate’s response is not worthy of credit according to the mark scheme. • Where some judgement is required, mark schemes will provide the principles by which marks will be awarded and exemplification may be limited. • When examiners are in doubt regarding the application of the mark scheme to a candidate’s response, the team leader must be consulted. • Crossed out work should be marked UNLESS the candidate has replaced it with an alternative response. Question Number Answer Additional Guidance Mark 1(a) Accept HO for OH (1) OH H OH H Question Number Answer Additional Guidance Mark 1(b) An answer that includes three of the following: • cellulose is made up of beta glucose (monomers) but starch is made up of alpha glucose (monomers) (1) • cellulose contains {unbranched / straight / linear} chains (of glucose) but starch contains branched chains (1) • cellulose contains 1,4 glycosidic bonds but starch contains 1,4 and 1,6 glycosidic bonds (1) • {inverted / flipped} glucose molecules in cellulose but glucose molecules in same orientation in starch (1) Piece 2 adjacent sentences only Accept b / β and a / α Accept cellulose contains one type of molecule but starch contains {two types / amylose and amylopectin} Accept amylose is coiled but cellulose is {not coiled / a straight chain molecule} Accept starch contains 1,6 glycosidic bonds but cellulose does not Accept a diagram