GCE Biology A H020/01: Breadth in biology Advanced Subsidiary GCE Mark Scheme for Autumn 2021

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GCE Biology A H020/01: Breadth in biology Advanced Subsidiary GCE Mark Scheme for Autumn 2021 GCE Biology A H020/01: Breadth in biology Advanced Subsidiary GCE Mark Scheme for Autumn 2021 Oxford Cam... bridge and RSA Examinations GCE Biology A H020/01: Breadth in biology Advanced Subsidiary GCE Mark Scheme for Autumn 2021Oxford Cambridge and RSA Examinations OCR (Oxford Cambridge and RSA) is a leading UK awarding body, providing a wide range of qualifications to meet the needs of candidates of all ages and abilities. OCR qualifications include AS/A Levels, Diplomas, GCSEs, Cambridge Nationals, Cambridge Technicals, Functional Skills, Key Skills, Entry Level qualifications, NVQs and vocational qualifications in areas such as IT, business, languages, teaching/training, administration and secretarial skills. It is also responsible for developing new specifications to meet national requirements and the needs of students and teachers. OCR is a not-for-profit organisation; any surplus made is invested back into the establishment to help towards the development of qualifications and support, which keep pace with the changing needs of today’s society. This mark scheme is published as an aid to teachers and students, to indicate the requirements of the examination. It shows the basis on which marks were awarded by examiners. It does not indicate the details of the discussions which took place at an examiners’ meeting before marking commenced. All examiners are instructed that alternative correct answers and unexpected approaches in candidates’ scripts must be given marks that fairly reflect the relevant knowledge and skills demonstrated. Mark schemes should be read in conjunction with the published question papers and the report on the examination. © OCR 2021H020/01 Mark Scheme October 2021 2 Annotations Annotation Meaning DO NOT ALLOW Answers which are not worthy of credit IGNORE Statements which are irrelevant ALLOW Answers that can be accepted ( ) Words which are not essential to gain credit __ Underlined words must be present in answer to score a mark ECF Error carried forward AW Alternative wording ORA Or reverse argumentH020/01 Mark Scheme October 2021 3H020/01 Mark Scheme October 2021 4 Question Answer Mark Guidance 1 B  1 2 C 1 3 B  1 4 D  1 5 D  1 6 B  1 7 C  1 8 D  1 9 A  1 10 D  1 11 C  1 12 D  1 13 A  1 14 D  1 15 B  1 16 D 1 17 A  1 18 A  1 19 D  1 20 C  1H020/01 Mark Scheme October 2021 5 Question Answer Mark Guidance 21 (a) (i) circle around the two nitrogen containing rings  1 e.g. 21 (a) (ii) ADP has 2 phosphates whereas DNA nucleotide (with adenine) has 1 phosphate  ADP has ribose whereas DNA (nucleotide with adenine) has deoxyribose  or ADP has OH on carbon 2 of sugar whereas DNA (nucleotide with adenine) has no OH on carbon 2 of sugar  2 Note: a clear comparison between ADP and DNA nucleotide must be made 21 (a) (iii) condensation  1 ALLOW phosphorylation - - -H020/01 Mark Scheme October 2021 6 21 (b) (i) 3 bases / triplet, code for 1 (specific) amino acid  sequence of, bases / triplets, determines the sequence of, amino acids / primary structure  (code) non-overlapping  AVP  2 max e.g. more than one codon codes for an amino acid / degenerate code is, universal / similar in eukaryotes and prokaryotes 21 (b) (ii) mechanical strength (to cells)  cell, support / stability / maintains shape  movement of (named), molecules / vesicles / organelles within cell OR holding organelles in position  formation / movement, of, cilia / flagella  cell movement / endocytosis / exocytosis / phagocytosis / cytokinesis / described  3 max IGNORE strength unqualified ALLOW maintain internal organisation 21 (b) (iii) movement of mRNA from nucleus to ribosome  movement of polypeptides through the rER  movement of vesicles from rER to Golgi  movement of vesicles between cisternae of Golgi (cis to trans face)  movement of secretory vesicles from Golgi to cell surface membrane 2 max Note: this requires more detail than part iiH020/01 Mark Scheme October 2021 7 Question Answer Mark Guidance 22 (a) use eyepiece graticule  calibrate graticule, using stage micrometer / detail of calibration / calculate the length of one epu  measure the diameter of the nucleus in, epu / graticule units  take repeat measurements and calculate a mean diameter (in epu)  use calibrated epu to calculate diameter (of nucleus) (in μm) / described  4 max e.g. of detail: align two scales and record number of divisions per graticule unit 22 (b) (i) laser scanning confocal microscope scanning electron microscope transmission electron microscope maximum resolution image appearance 3D 2D  image colour named colour /coloured black and white  Mark each row 22 (b) (ii) larger number of (named) organelles  more DNA / larger nucleus  no visible chromosomes  nuclear membrane present  2 max ALLOW twice as much DNAH020/01 Mark Scheme October 2021 8 22 (c) (i) wbc do not have cell walls to break open  wbc are, individual cells / not a tissue, so no separation needed  1 max 22 (c) (ii) disrupts / breaks down / dissolves, phospholipid bilayer / membrane  1 ALLOW remove bilayer / membrane 22 (c) (iii) (named) protease  break down, histones / proteins associated with DNA  2 ALLOW hydrolyticH020/01 Mark Scheme October 2021 9 Answer Mark Guidance 23 (a) (i) the volume of air in chamber decreases  (spirometer air) contains less O2 as absorbed by lungs  CO2 (in exhaled air) is absorbed by soda lime  2 max 23 (a) (ii) 13  2 ALLOW 12.8 – 13 ALLOW one mark for: 9 breaths in 42s 8 breaths in 37s ALLOW one mark for ECF for correct calculation using incorrect data 23 (a) (ii) 2900  2 ALLOW 2800 – 3000 max 1 mark for 2.9 ALLOW 2.8 – 3.0 for one mark 23 (b) (i) in boys (mtv) increases with age (from 13) up to 16 then plateau  in girls (mtv) shows little variation from 12 – 19  range of values in boys always larger than in girls (except 13)  mean / maximum, volume in boys larger than in girls (except 13)  3 maxH020/01 Mark Scheme October 2021 10 23 (b) (ii) girls and 13  only group where girls mean is above boys  OR boys and 16  upper range bar much higher than 15 and 17  2 mark as pairs of answers ALLOW does not fit rising trend in girls age 12 –15 ALLOW upper end of range bar higher than all others for girls 23 (b) (iii) (standard deviation shows) spread of data compared to mean  reduces the effect of an anomaly (in a data point at the extreme of the range)  2 23 (b) (iv) 103  3 ALLOW evidence of (√)74000 / 7 OR 102.8(174527) for 2 marks ALLOW = 74000 for 1 mark 23 (b) (v) idea of: random selection (of participants)  (select) healthy participants  (select) participants who are rested  idea of: sample to include a range of, fitness / height / size / build  equal numbers boys and girls  equal numbers in each age group  2 maxH020/01 Mark Scheme October 2021 11 24 (a) (i) any three from: greater use / overuse / over prescription, of methicillin  not completing course (of methicillin)  idea of: use (of methicillin) in farming  natural selection of MRSA  idea that: large % increase (in a short time) due to fast generation time  3 max 24 (a) (ii) idea of: universal language  shows evolutionary relationship between species (at the genus level)  1 max 24 (b) (i) cell wall  (named) metabolic reaction  reproduction of bacterium  1 max e.g. protein synthesis 24 (b) (ii) many drugs, found in / originated from, plants / microbes  (so, maintaining biodiversity) increase the chance of, finding / developing, new drugs  maintains a genetic resource (for future)  idea that: once a species is extinct it’s gone forever  2 max ALLOW forestH020/01 Mark Scheme October 2021 12 24 (c) idea that: choice / development, of (more effective), drug / treatment, linked to, genotype / genes / individual  GMOs to produce, drug / useful molecule / enzyme  OR synthesis of new genes / organisms  2 ALLOW named example e.g. GM E. coli making human insulin GM mammals making drugs with milk proteins monoclonal antibodies for targeted drug deliveryOCR (Oxford Cambridge and RSA Examinations) The Triangle Building Shaftesbury Road Cambridge CB2 8EA OCR Customer Contact Centre Education and Learning Telephone: 01223 553998 Facsimile: 01223 552627 Email: general.qualifications@ocr.org.uk [Show More]

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