Mark Scheme for A Level Biology B Practice Paper Set 1, Exams of Biology

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Practice paper – Set 1.

A Level Biology B (Advancing Biology) H422/01 Fundamentals of biology

MARK SCHEME

Duration: 2 hours 15 minutes

MAXIMUM MARK 110

H422/01 Mark Scheme Practice paper - Set 1

FINAL

This document consists of 16 pages MARKING INSTRUCTIONS PREPARATION FOR MARKING SCORIS

1. Make sure that you have accessed and completed the relevant training packages for on-screen marking: scoris assessor Online Training ; OCR Essential Guide to Marking.
2. Make sure that you have read and understood the mark scheme and the question paper for this unit. These are posted on the RM Cambridge Assessment Support Portal http://www.rm.com/support/ca
3. Log-in to scoris and mark the required number of practice responses (“scripts”) and the required number of standardisation responses. YOU MUST MARK 10 PRACTICE AND 10 STANDARDISATION RESPONSES BEFORE YOU CAN BE APPROVED TO MARK LIVE SCRIPTS.

MARKING

1. Mark strictly to the mark scheme.
2. Marks awarded must relate directly to the marking criteria.
3. The schedule of dates is very important. It is essential that you meet the scoris 50% and 100% (traditional 50% Batch 1 and 100% Batch 2) deadlines. If you experience problems, you must contact your Team Leader (Supervisor) without delay.
4. If you are in any doubt about applying the mark scheme, consult your Team Leader by telephone, email or via the scoris messaging system. H422/01 Mark Scheme Practice paper - Set 1
5. Work crossed out: a. where a candidate crosses out an answer and provides an alternative response, the crossed out response is not marked and gains no marks b. if a candidate crosses out an answer to a whole question and makes no second attempt, and if the inclusion of the answer does not cause a rubric infringement, the assessor should attempt to mark the crossed out answer and award marks appropriately.
6. Always check the pages (and additional objects if present) at the end of the response in case any answers have been continued there. If the candidate has continued an answer there then add a tick to confirm that the work has been seen.
7. There is a NR (No Response) option. Award NR (No Response)

• if there is nothing written at all in the answer space
• OR if there is a comment which does not in any way relate to the question (e.g. ‘can’t do’, ‘don’t know’) - OR if there is a mark (e.g. a dash, a question mark) which isn’t an attempt at the question.

H422/01 Mark Scheme Practice paper - Set 1 Note: Award 0 marks – for an attempt that earns no credit (including copying out the question).

8. The scoris comments box is used by your Team Leader to explain the marking of the practice responses. Please refer to these comments when checking your practice responses. Do not use the comments box for any other reason. If you have any questions or comments for your Team Leader, use the phone, the scoris messaging system, or email.
9. Assistant Examiners will send a brief report on the performance of candidates to their Team Leader (Supervisor) via email by the end of the marking period. The report should contain notes on particular strengths displayed as well as common errors or weaknesses. Constructive criticism of the question paper/mark scheme is also appreciated.
10. For answers marked by levels of response: Read through the whole answer from start to finish, concentrating on features that make it a stronger or weaker answer using the indicative scientific content as guidance. The indicative scientific content indicates the expected parameters for candidates’ answers, but be prepared to recognise and credit unexpected approaches where they show relevance. Using a ‘best-fit’ approach based on the science content of the answer, first decide which set of level descriptors, Level 1, Level 2 or Level 3, best describes the overall quality of the answer using the guidelines described in the level descriptors in the mark scheme. Once the level is located, award the higher or lower mark. The higher mark should be awarded where the level descriptor has been evidenced and all aspects of the communication statement (in italics) have been met. The lower mark should be awarded where the level descriptor has been evidenced but aspects of the communication statement (in italics) are missing. In summary:
    • The science content determines the level.
    • The communication statement determines the mark within a level. Level of response questions on this paper are 32(b) and 34(c).

H422/01 Mark Scheme Practice paper - Set 1

11. 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 argument AVP Alternative valid points

H422/01 Mark Scheme Practice paper - Set 1 4

12. Subject-specific Marking Instructions INTRODUCTION Your first task as an Examiner is to become thoroughly familiar with the material on which the examination depends. This material includes:
    • the specification, especially the assessment objectives • the question paper
    • the mark scheme. You should ensure that you have copies of these materials. You should ensure also that you are familiar with the administrative procedures related to the marking process. These are set out in the OCR booklet Instructions for Examiners. If you are examining for the first time, please read carefully Appendix 5 Introduction to Script Marking: Notes for New Examiners. Please ask for help or guidance whenever you need it. Your first point of contact is your Team Leader.

SECTION A

• H422/01 Mark Scheme Practice paper - Set - 1 B  Question Answer Marks Guidance - 2 A  - 3 D  - 4 C  - 5 B  - 6 A  - 7 A  - 8 C  - 9 D 
  • 10 A 
  • 11 C 
  • 12 A 
  • 13 C 
  • 14 C 
  • 15 D 
  • 16 C 
  • 17 A 
  • 18 D 

H422/01 Mark Scheme Practice paper - Set 1 19 B  1 20 B  1 21 A  1 22 C  1 23 B  1 24 C  1 25 C  1 26 C  1 27 B  1 28 C  1 29 B  1 30 D  1 Total 30 SECTION B Question Answer Marks Guidance 31 (a) E / F  F  A  D 

ALLOW C in place of A. (b) (i) any 3 from : shows which parts of brain are active  magnetic properties of oxyhaemoglobin and deoxyhaemoglobin different  higher blood flow / oxygen uptake, in active regions  greater emission of radio signal from active regions 

ALLOW oxygenated/deoxygenated blood ALLOW hb for haemoglobin ORA ORA

H422/01 Mark Scheme Practice paper - Set 1 produces 3D image  IGNORE ref to brain damage (ii) any 2 from : real-time measurement / CT only gives still image  view brain activity directly  greater soft tissue detail / contrast / resolution  no need for, dyes / contrast agents  no exposure to radiation 

IGNORE ref to safety unqualified (iii) electroencephalography / EEG  1 ALLOW magnetoencephalography / MEG Total 10 Question Answer Marks Guidance 32 (a) (i) group of organisms that interbreed (to produce fertile offspring)  similarity of genetic / physiological / behavioural attributes 

(ii) Domain Eukarya / Eukaryota  Phylum  2 DO NOT ALLOW eukaryote(s) ALLOW lowercase initial letters 16 Question Answer Marks Guidance

H422/01 Mark Scheme Practice paper - Set 1 (b)* Read through the whole answer from start to finish, concentrating on features that make it a stronger or weaker answer using the indicative scientific content as guidance. The indicative scientific content indicates the expected parameters for candidates’ answers, but be prepared to recognise and credit unexpected approaches where they show relevance. Using a ‘best-fit’ approach based on the science content of the answer, first decide which set of level descriptors, Level 1, Level 2 or Level 3, best describes the overall quality of the answer using the guidelines described in the level descriptors in the mark scheme. Once the level is located, award the higher or lower mark. The higher mark should be awarded where the level descriptor has been evidenced and all aspects of the communication statement (in italics) have been met. The lower mark should be awarded where the level descriptor has been evidenced but aspects of the communication statement (in italics) are missing. In summary:

• The science content determines the level.
• The communication statement determines the mark within a level. Level 3 (5–6 marks) Provides a comprehensive explanation of the speciation process, including the ideas of geographical isolation, selection pressures and adaptations. There is a well-developed line of reasoning which is clear and logically structured and uses scientific terminology at an appropriate level. All the information presented is relevant and forms a continuous narrative. Level 2 (3–4 marks) Provides an outline of the speciation process, with some ideas about geographical isolation, selection pressures and/or adaptations. 6 Indicative scientific points may include
• geographical isolation / allopatric speciation / canyon is physical barrier
• (different) selection pressures for each population / in North/South rim areas
• example of selection pressure difference
• (original) gene pool had allelic variation
• different mutations (in separated populations)
• alleles / mutations may provide improved adaptation to environment
• mutations / alleles passed to offspring;
• by surviving / selected individuals IGNORE genes passed to offspring

H422/01 Mark Scheme Practice paper - Set 1 Question Answer Marks Guidance There is a line of reasoning presented with some structure and use of appropriate scientific language. The information presented is mostly relevant. Level 1 (1–2 marks) Shows limited understanding of the speciation process, which may include the idea of geographical isolation. There is a logical structure to the answer. The explanation, though basic, is clear. 0 marks No response or no response worthy of credit.

• change in allele frequencies / genetic variation between populations • genetic drift
• past bottleneck event Total 10 Question Answer Marks Guidance 33 (a) any 3 from : (role is) to set up a range of water potential gradients between medullary tissue fluid and collecting duct  diffusion of water out of descending limb  ion concentration high at base of loop  sodium and chloride ions diffuse out of base of ascending limb  water cannot leave ascending limb / ascending limb impermeable to water  ions pumped out of upper ascending limb 

(b) (i) ((110 – 90) ÷ 110 ) x 100 OR (20 ÷ 110) / 100 2 ALLOW 1 mark for correct method of calculation 1

H422/01 Mark Scheme Practice paper - Set 1 18 / 18.2 %  ALLOW 18.18 % DO NOT ALLOW more than 2 d.p. Question Answer Marks Guidance (ii) any 3 from : cuff of sphygmomanometer cuts off blood flow  to brachial artery (of arm)  stethoscope used to listen to blood flow  cuff slowly relaxed / valve released  first sound indicates systolic pressure  disappearance of sound indicates diastolic pressure 

(c) (i) any 3 from : risk generally increased with a decrease in GFR  risk little affected by an increase in urinary protein  GFR of 60+ ml / min has little influence with urinary protein < 34 mg / mmol  correct quotation of figures in support of any statement 

(ii) any 3 from : not a representative cross-section  in hospital so already sick  may have other illnesses / complications  limitation of medications they can use  may not have comparable treatments  probably skewed towards elders / younger people under-represented  doesn’t account for subjects who died after a year  doesn’t account for length of time with CKD before admission 

(iii) enlarge the cohort  adapt method, e.g. more hospitals, over longer time, take records of non-hospitalised cases 

Total 15 1

H422/01 Mark Scheme Practice paper - Set 1 Question Answer Marks Guidance 34 (a) (i) Rhizobium  1 ALLOW Sino/Meso/Brady/Azorhizobium ALLOW not italicised DO NOT ALLOW lowercase r (ii) image size ÷ magnification OR 15,000 ÷ 32,000  0.47 / 0.5  2 ALLOW 2 marks for correct answer without working ALLOW 0. (b) (i) any 3 from : (active transport) into root hairs  apoplast / symplast pathway  through epidermis / cortex layers  via xylem vessel to (root) nodule 

(ii) Krebs cycle  1 ALLOW TCA cycle / citric acid cycle 1

H422/01 Mark Scheme Practice paper - Set 1 (c)* Read through the whole answer from start to finish, concentrating on features that make it a stronger or weaker answer using the indicative scientific content as guidance. The indicative scientific content indicates the expected parameters for candidates’ answers, but be prepared to recognise and credit unexpected approaches where they show relevance. Using a ‘best-fit’ approach based on the science content of the answer, first decide which set of level descriptors, Level 1, Level 2 or Level 3, best describes the overall quality of the answer using the guidelines described in the level descriptors in the mark scheme. Once the level is located, award the higher or lower mark. The higher mark should be awarded where the level descriptor has been evidenced and all aspects of the communication statement (in italics) have been met. The lower mark should be awarded where the level descriptor has been evidenced but aspects of the communication statement (in italics) are missing. In summary:

• The science content determines the level.
• The communication statement determines the mark within a level. Question Answer Marks Guidance 1

H422/01 Mark Scheme Practice paper - Set 1 Level 3 (5–6 marks) A detailed discussion of how to use a biosensor to monitor nitrate concentration, including many ways to ensure validity of the data obtained. The requirement for the standard curve is mentioned. There is a well-developed line of reasoning which is clear and logically structured and uses scientific terminology at an appropriate level. All the information presented is relevant and forms a continuous narrative. Level 2 (3–4 marks) A good discussion of how to use a biosensor to monitor nitrate concentration, including several ways to ensure validity of the data obtained. The requirement for the standard curve may be mentioned. There is a line of reasoning presented with some structure and use of appropriate scientific language. The information presented is mostly relevant. Level 1 (1–2 marks) A limited discussion of how to use a biosensor to monitor nitrate concentration, with only some ways to ensure validity of the data obtained. The requirement for the standard curve is not mentioned. There is a logical structure to the answer. The explanation, though basic, is clear. 0 marks No response or no response worthy of credit. 6 Indicative scientific points may include

• regular sampling
• in the same site(s)
• same volume of water
• same number of, bacteria / biosensors
• same temperature of water (for enzyme activity)
• ref to repeats
• taken from set points around the lake or along the stream
• nitrate / NO 3 -^ concentration, read from, standard curve / standards (derived from the calibration)
• calculation of means
• identifying trends
• continue over time / specify length of investigation
• same light meter
• same sample-taker / meter operator Total 13 1

H422/01 Mark Scheme Practice paper - Set 1 Question Answer Marks Guidance 35 (a) (i) A: any 2 from : (di)sulfide, bonds / bridges  covalent bonds  between cysteine amino acids / S-S atoms / S-H groups  B: alpha helix  hydrogen bonding / interactions, between –NH (group) of one amino acid and –CO (group) of another 

disulfide bonds are covalent = 2 marks DO NOT ALLOW disulfate IGNORE ref to carbohydrate chains (ii) any 3 from : transported to Golgi (apparatus / body / complex)  glycosylated / sugar / carbohydrate added using glycosylase / enzymes  packaged into / formation of (secretory) vesicles  fusion of vesicles with, plasma / cell surface, membrane 

(b) (i) any 2 from : FSH & LH not released  follicle not stimulated / oocyte does not develop (by FSH)  no ovulation (by LH) 

(ii) 2.6  2 ALLOW 2. ALLOW ECF for 1 mark unrounded number (2.58844…) = 1 mark (iii) FL more effective than G, due to higher mean pregnancies  Data for FL overlap with G / FL gives more variable effectiveness 

(iv) dose of hormones (e.g. per g body mass)  age of each male  1 AVP e.g. sexual activity of male Total 14 1

H422/01 Mark Scheme Practice paper - Set 1 Question Answer Marks Guidance 36 (a) (i) Z: crista(e)  large surface area, for oxidative phosphorylation / ATP production 

(ii) establish, H+^ / proton gradient, across inner membrane  1 (b) (i) H+^ / electrochemical gradient / proton motive force, lost  ATP synthase stops / ATP not produced / uncoupling of electron transport from ATP synthesis 

(ii) less / loss of, cytochrome C (from intermembrane space)  reduction in / loss of, electron transfer / shuttling between, complexes / carriers  2 DO NOT ALLOW ref to moving of cytochrome C without idea of loss / deficiency in intermembrane space (iii) (reduced NAD/reduced FAD) oxidised on inner membrane / inner membrane not affected 

Total 8 Question Answer Marks Guidance 37 (a) (i) number of new cases, over time / within time period / over a year  1 (ii) any 3 from : 3 1

H422/01 Mark Scheme Practice paper - Set 1 no information on population size  different countries have different population size  use of correct figures from table in support  different reporting procedures  accuracy of diagnosis  ALLOW ‘not given per 100 000’ or ‘not given as % of population e.g. ‘there are 349 deaths in China but only 41 in Canada but China has a bigger population’ gets marking points 2 and 3 Question Answer Marks Guidance (b) (i) (13 000 – 1000) / 15  800  2 800 = 2 marks ALLOW ecf for marking point 2 (ii) rapid rise in cases in first 25 days  no further cases / contained, after 50 days OR idea that outbreak lasted 50 days  no deaths after 50 days  idea that cases that resulted in death is only a small proportion of all cases  figures to support above statement  quarantine rate proportional to rate of new cases  4 ALLOW 20 – 30 days ALLOW 45 – 50 days ALLOW 45 – 50 days e.g. 180 – 190 cases but 35 – 40 deaths. Total 10 1