Edexcel as level biology paper 2 mark scheme june 2023 salters nuffield

Mark Scheme (Results) Summer 2023 Pearson Edexcel GCE In Biology Spec A (8BN0) Paper 02 Development, Plants and the EnvironmentEdexcel and BTEC Qualifications Edexcel and BTEC qualifications come from Pearson, the world’s leading learning company. We provide a wide range of qualifications including academic, vocational, occupational and specific programmes for employers. For further information, please visit our website at . Our website subject pages hold useful resources, support material and live feeds from our subject advisors giving you access to a portal of information. If you have any subject specific questions about this specification that require the help of a subject specialist, you may find our Ask The Expert email service helpful. Pearson: helping people progress, everywhere 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 Publications Code 8BN0_02_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 Mark 1(a) The only correct answer is – D Golgi apparatus, mitochondria and rough endoplasmic reticulum A is incorrect because animal cells do not have amyloplasts or chloroplasts B is incorrect because animal cells do not have amyloplasts C is incorrect because animal cells do not have a cell wall (1) Question Number Answer Mark 1(b) The only correct answer is – C the nucleus divides A is incorrect because the cell divides after mitosis is completed B is incorrect because the cell membrane does not break down during mitosis D is incorrect because the organelles do not multiply during mitosis (1) Question Number Answer Mark 1(c)(i) The only correct answer is – A anaphase B is incorrect because the cell is not in metaphase C is incorrect because the cell is not in prophase D is incorrect because the cell is not in telophase (1)Question Number Answer Mark 1(c)(ii) The only correct answer is – C 7 : 1 A is incorrect because 9 : 1 is not approximate to 873:127 B is incorrect because 9 : 2 is not approximate to 873:127 D is incorrect because 7 : 2 is not approximate to 873:127 (1) Question Number Answer Additional guidance Mark 1(c)(iii) A description that makes reference to four of the following: • spindle fibres break down (1) • chromosomes {decondense / uncoil} (1) • nucleoli form (1) • nuclear {membrane / envelope } forms (1) • two separate { nuclei / sets of chromosomes }(1) ALLOW nucleolus reforms ALLOW sets of chromosomes at opposite sides of the cell (4)Question Number Answer Additional guidance Mark 2(a) A description that makes reference to the following: • nitrates are used to make {amino acids / protein} (1) • { growth is reduced / plants are stunted } if nitrates are lacking (1) • (nitrates) needed to make { nucleic acids / DNA / RNA / ATP / chlorophyll } (1) ALLOW proteins needed for growth ALLOW nitrogenous bases (3) Question Number Answer Mark 2(b)(i) The only correct answer is D chlorophyll A is incorrect because there is no magnesium in amylose B is incorrect because there is no magnesium in calcium pectate D is incorrect because there is no magnesium in cellulose (1)Question Number Answer Additional guidance Mark 2(b)(ii) An answer that makes reference to four of the following: • use of plants that are {clones / same age / same variety} (1) • provide a range of magnesium ion concentrations (1) • two abiotic factors to be controlled (1) • grown for the same given time period (1) • relevant method for growth to be measured (1) • repeats at each concentration to calculate a mean (1) ALLOW same type / same species ALLOW (minimum of) 5 different concentrations IGNORE units e.g. temperature / light intensity / volume of water / other mineral ion concentration ALLOW time in units of days / weeks / months e.g. height/length of shoot or root, ma