Edexcel a level biology question paper 1 ju ne 2023 + mark scheme

Mark Scheme (Results) Summer 2023 Pearson Edexcel GCE In Biology B (9BI0) Paper 01: Advanced Biochemistry, Microbiology, and GeneticsEdexcel 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 P71909A Publications Code 9BI0_01_2306_MS All the material in this publication is copyright © Pearson Education Ltd 2023General 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)(i) • (calcium) pectate (1) IGNORE middle lamella DO NOT ACCEPT any other molecule (1) Question Number Answer Mark 1(a)(ii) The only correct answer is C A is incorrect because statements 1 and 2 are correct and statement 3 is incorrect B is incorrect because statements 1 and 2 are correct and statement 3 is incorrect D is incorrect because statements 1 and 2 are correct and statement 3 is incorrect (1)Question Number Answer Additional Guidance Mark 1(b) An explanation that makes reference to four of the following: • (decrease in concentration) due to K+ {leaving (cell) / being used in synthesis of correct named molecule} AND (increase in concentration) due to K+ being taken up (by cell) (1) • ions decrease {by (facilitated) diffusion / move down a concentration gradient} (1) • ions taken up by active transport (1) • (in aerobic conditions) oxygen available for aerobic respiration (1) • aerobic respiration generates (more) {ATP / energy} (1) PIECE TOGETHER ACCEPT active transport cannot take place in anaerobic conditions ACCEPT converse ACCEPT converse (4) Question Number Answer Additional Guidance Mark 2(a) An explanation that makes reference to the following: • not Bacteria as Archaea do not have a peptidoglycan cell wall (1) • not Eukaryota as these organisms {have 70S ribosomes / do not have a nucleus} (1) IGNORE refs to gram negative and gram positive bacteria prokaryotes DO NOT ACCEPT if wrong reason given as well ACCEPT do not have 80S ribosome IGNORE refs to other membrane-bound organelles DO NOT ACCEPT if wrong reason given as well (2)Question Number Answer Additional Guidance Mark 2(b)(i) An answer that makes reference to three of the following: • (two enzymes) because enzymes found in different locations (1) • pH is different / their substrates are found in different locations (1) • (two enzymes) because their substrates are different (1) • therefore their active site will be different {shape / structure} (1) • {similar structure / both are AK enzymes / both are kinases} because both {are transferring phosphate / have similar roles (1) IGNORE incorrect explanations of what the enzymes are doing with ATP and GTP ACCEPT enzymes cannot move between mitochondria and cytoplasm ACCEPT ATP in cytoplasm and GTP in mitochondria ACCEPT because one uses ATP and the other uses GTP (3) Question Number Answer Additional Guidance Mark 2(b)(ii) An explanation that makes reference to two of the following: • Archaea {do not have mitochondria / only have cytoplasm} so do not need two enzymes (1) • {pH / temperature} of Archaea different to human’s (1) • Archaea’s enzymes need to be able to {bind / fit} to {two substrates / both ATP and GTP} (1) • {genetic code / (DNA) base sequence} is different OR different primary structure (1) ACCEPT need to form ESCs with different substrates NB ref to induced-fit may access this point provided in the context of substrate (2)Question Number Answer Additional Guidance Mark 3(a) • (a group of similar) cells that perform a similar function (1) (1