Pearson Edexcel AS Level GCE

Mark Scheme (Results) Summer 2025 Pearson Edexcel AS Level GCE In Biology A Salters Nuffield (8BN0) Paper 01: Lifestyle, Transport, Genes and Health 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 2025 Question Paper Log Number P78687A Publications Code 8BN0_01_2506_MS All the material in this publication is copyright © Pearson Education Ltd 2025 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 Mark 1(a)(i) D- uracil A is incorrect because adenine is present in DNA B is incorrect because guanine is present in DNA C is incorrect because thymine is present in DNA (1) Question Number Answer Mark 1(a)(ii) B- DNA is double-stranded and messenger RNA is single stranded A is incorrect because messenger RNA is single-stranded C is incorrect because messenger RNA is single-stranded D is incorrect because DNA is double-stranded (1) Question Number Answer Mark 1(b)(i) D- phosphodiester A is incorrect because mononucleotides are joined by phosphodiester bonds B is incorrect because mononucleotides are joined by phosphodiester bonds C is incorrect because mononucleotides are joined by phosphodiester bonds (1) Question Number Answer Additional Guidance Mark 1(b)(ii) An answer that makes reference to three of the following: • DNA replication uses DNA nucleotides whereas transcription uses RNA nucleotides (1) • DNA replication uses DNA polymerase whereas transcription uses RNA polymerase (1) • DNA replication copies both strands whereas transcription copies {one / template} strand (1) • DNA replication forms {a DNA double helix / double stranded DNA} whereas transcription forms single stranded (m)RNA (1) ALLOW DNA replication is semi- conservative whereas transcription is not IGNORE replication making 2 {strands / molecules} and transcription making 1 {strand / molecule} (3) Question Number Answer Additional Guidance Mark 2(a)(i) An answer that makes reference to the following: • ATP provides {energy / is energy source} for {active transport of molecules / movement of molecules against concentration gradient / carrier protein (T) to change shape} (1) ALLOW ATP provides energy to {pump /move} molecules (through component T) (1) Question Number Answer Additional Guidance Mark 2(a)(ii) A description that makes reference to the following: • by facilitated diffusion (1) • (diffusing) from a higher concentration to a lower concentration / down a concentration gradient (1) ALLOW diffusion through a hydrophilic channel (2) Question Number Answer Additional Guidance Mark 2(b)(i) osmosis (1) IGNORE (simple) diffusion (1) Question Number Answer Additional Guidance Mark 2(b)(ii) An explanation that makes reference to the following: • Q has two saturated fatty acids whereas R has one saturated fatty acid and one unsaturated fatty acid (1) • (unsaturated fatty acids) contain (carbon to carbon) double bond(s) which cause a kink (1) ALLOW Q has saturated fatty acids whereas R has unsaturated fatty acid(s) / R has an unsaturated fatty acid and Q does not IGNORE fat (2) Question Number Answer Additional Guidance Mark 2(b)(iii) An answer that makes reference to the following: • (increasing proportion of S would) increase {the fluidity / permeability} (of the cell membrane) (1)