GCE. Human Biology. Mark Scheme for June Unit F222: Growth, Development and Disease. Advanced Subsidiary GCE

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1 GCE Human Biology Unit F222: Growth, Development and Disease Advanced Subsidiary GCE Mark Scheme for June 2017 Oxford Cambridge and RSA Examinations

2 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 will not enter into any discussion or correspondence in connection with this mark scheme. OCR 2017

3 Annotations used in the detailed Mark Scheme (to include abbreviations and subject-specific conventions). Annotation Meaning Correct answer Incorrect response Benefit of Doubt Not Benefit of Doubt Error Carried Forward Given mark Underline (for ambiguous/contradictory wording) Omission mark Ignore Correct response (for a QWC question) QWC* mark awarded Verbal Construction *Quality of Written Communication 3

4 Question Answer Marks Guidance 1 a i Woman A too much/more, energy and (could lead to) obesity / cardiovascular disease / angina / diabetes ; 4 max Mark as prose. IGNORE values without further clarification too little/less, vitamin A and weak(er) immune system/ retinal dysfunction/ corneal dysfunction/ poor collagen (formation) ; ACCEPT deficiency in /lack of, Vitamin A ACCEPT named part e.g. collagen/ cornea more protein and (problems with) kidney (function) ; Woman B too little/less, vitamin C and (problems with) skin / bones / tendons /collagen formation/blood clotting ; too little/less folic acid and (problems with development of) fetal nervous system ; ACCEPT deficiency in/ lack of, Vitamin C ACCEPT in the context of mother or baby DO NOT ACCEPT in the context of the adult nervous system ACCEPT neural tube defects / spina bifida ii phosphate ; calcium (ions) ; vitamin D ; b i 1. less sugar in diet (will control blood glucose levels) ; 2. insulin (injections) will not control blood glucose levels ; 3. (because) insulin still produced (in type 2 diabetes) ; 4. (type 2 diabetics liver/muscle is) insensitive/aw, to insulin ; IGNORE reference to sources of nutrients such as milk or dairy products Mark first answer on each line 4

5 ii C D E B ;;; 3 C first = 1 mark D before E = 1 mark B last = 1 mark iii 1. (if) glycated haemoglobin (concentration) low, guidelines followed ora ; 2. High glycated haemoglobin (concentration) means (regular) high (plasma) glucose concentration ora ; 3. (glycated haemoglobin) does not fluctuate (e.g. with food intake) ; 4. (results valid for) 1 month/ long(er) term ; c 1. (reduced salt intake) reduced/lower, blood pressure ; ora 2. (reduced saturated fat results in) reduced LDL cholesterol; ora 3. (increased) activity lowers blood, pressure /cholesterol ; ora 3 IGNORE reference to secondary effects e.g. plaque formation/obesity. ACCEPT less/no, hypertension for blood pressure. d i 1.52 ;; 2 Correct answer is 2 marks even if no working shown ii bypass surgery (risk of ) infection / arrythmia ; Otherwise, Award ONE mark for: 2.30 / IGNORE reference to anaesthetic dangers /bleeding/ blood clots as this applies to all 3 in equal measure. blood vessel/vein, (maybe) removed from (another) area of body ; 1 max angioplasty (risk of ) allergy (to dye or stent) ; DO NOT ACCEPT artery/capillary 5

6 (risk of ) scar tissue (around stent) ; 1 max transplant risk of rejection ; long waiting list / shortage of (suitable) donors ; 1 max Total 21 Question Answer Marks Guidance 2 a i 18 year old male with Down syndrome (DS) 1. short(er) (compared to adult male without DS) ; 3 max IGNORE reference to any age under 18 ACCEPT ora throughout 2. correct use of comparative data (18 years) to support mp 1 ; 3. more, have high(er) weight/are fat(ter) AND more, have low(er) weight/ are thin(ner) ; e.g. (50 th centile) height for normal 18 year old is 175(cm) and for Down Syndrome 18 year old is 152(cm). 4. more between kg ; 5. more between 40-50kg ; ACCEPT any value within the ranges for mp 3 and 4 6

7 b ii 5.43 / 5.4 ; ; cm yr -1 ; Error: Absolute growth rate is a better measure, (Should read) relative (growth rate) / ( absolute growth rate is a ) worse measure ; 3 CREDIT any correct number of decimal places. 4 ONE mark for: OR 37.5 ACCEPT year for yr Error: Cells differentiate and are organised into organs which are grouped into tissues, (Should read ) organised into tissues which are grouped into organs ; ACCEPT organised into organs which are grouped into organs systems. Error: The lymphatic system grows fastest during first five years of life, (Should read) The nervous system (grows fastest)/ (grows fastest) between 8-12 years ; ACCEPT any value within this range Error: called the thymus where B lymphocytes mature, (Should read) where T lymphocytes (mature) ; 7

8 c i Turner s (syndrome) ; 1 ii any correct symptom of Klinefelter s syndrome, including: feminised physique, small testes, poor growth of body hair ; 1 d 1. oxygen supply to fetus reduced ; 3 max 2. nicotine reduces diameter of blood vessels in, placenta / fetus ; 3. carbon monoxide binds to haemoglobin ; 4. less (fetal) aerobic respiration / ATP synthesis ; 5. less (fetal) protein synthesis (for growth) ; e.g. breast development Total 15 Question Answer Marks Guidance 3 a i (reduces) stickiness of platelets ; ii (reduces risk of) blood clots in coronary artery ; Heart attack Symptoms HS1 chest pain ; HS2 irregular pulse/ weak pulse / irregular heart rhythm ; HS3 vomiting / nausea ; HS4 cold extremities/ cold sweats ; Treatment HT1 give person relevant (named) medication ; HT2 (supported) sitting position ; Cardiac arrest Symptoms: 4 max 2 IGNORE thins blood OR anticoagulant 6 max IGNORE reference to subsequent treatments as this could be similar for both. ACCEPT beta blockers/aspirin/nitroglycerin 8

9 CS1 no, pulse / (regular) heart beat ; CS2 loss of consciousness ; CREDIT ref. to (ventricular) fibrillation Treatment: CT1 cardio-pulmonary resuscitation / CPR / described ; CT2 use defibrillator ; QWC 1 Total 9 Award QWC if at least one HS, one HT, one CS and one CT mark have been awarded Question Answer Marks Guidance 4 a i 3 ; ; ; 9

10 ii 1. (provides) stability ; 2. either strand can act as a template / allows semi-conservative replication ; 3. allows proof-reading ; 4. (so) fewer (point) mutations ; iii 1. (DNA) helicase, breaks hydrogen bonds / unzips DNA ; 2. (DNA) gyrase/topoisomerase unwinds DNA helix ; 3. DNA polymerase, produces new DNA strand (by forming phosphodiester bonds) ; 4. (DNA) exonuclease / DNA polymerase, proof-reads ; 5. (DNA) ligase joins (Okazaki) fragments of DNA ; 3 max IGNORE reference to unwinds DNA for helicase DO NOT ACCEPT ref to hydrogen bonds b Statement Apoptosis Mitosis Meiosis 3 One mark for each correct column ACCEPT alternative indication of answer (e.g. ) The cell shrinks Essential for growth and repair Nuclear envelope disintegrates Has a set sequence of events Results in identical daughter cells ; ; ; Total 11 10

11 Question Answer Marks Guidance 5 a Description 1. male smoking and cancer, rates are falling (over time) ; 2. female smoking (rate) is falling but female cancer rate is (still) rising ; 3. decrease in male lung cancer (rate) lags behind decrease in male smoking (rate) ; 4. data to support any marking point with correct units (at least once) ; Explanation 5. (cigarette) smoke contains carcinogens ; 6. smoking is not the only causative factor (for lung cancer) ; 7. cancer takes time to develop ; max 3 4 max b i 1. damages, healthy/non-cancerous, cells, with a high rate of (cell) division/ actively dividing ; ii 2. example of cell type ; 3. interferes with mitosis ; Seed banks 1. plants can be sources of medicine ; 2. seed banks, conserve species / maintains biodiversity ; 3. genetic resource ; DNA analysis 4. DNA barcodes ; 5. can be used to identify medicinal properties ; e.g. cells in skin, bone marrow, hair follicles 4 max IGNORE ref to personalised medicines as DNA analysis is in context of plants/seeds ACCEPT prevent extinction of species DNA barcodes can be used to identify 11

12 6. comparisons of different plants (for medicinal properties) ; medicinal properties = 2 marks iii cancerous cells are dividing but (most) healthy cells are not ; 1 max (radiotherapy) destroys, (only) dividing / actively growing, cells ; iv (uses monoclonal) antibodies (for cancer antigens) ; 1 IGNORE protein/polypeptide c obstructive pulmonary ; 4 inhibitor ; coughs ; scar ; Total 16 Question Answer Marks Guidance 6 a i (a disease that can be) passed between organisms and caused by 1 pathogens ; ii similarities 3 max 1. capsid / described ; ACCEPT description of protein shell 2. (outer) envelope ; 3. glycoproteins / antigens (on surface) ; differences 4. HIV has RNA (not DNA) ; 5. HIV has reverse transcriptase (not DNA polymerase) ; iii 1. amplifies (HIV) DNA ; 2. from (infected) white blood cells / leucocytes ; 3. (tests for) viral load ; 12

13 4. (tests on) new born babies ; b B lymphocytes 1. develop into plasma cells ; 2. produce / release / secrete, antibodies ; 3. (antibodies involved in) neutralisation ; 7 max T lymphocytes 4. T helper, cells / lymphocyte ; 5. produce / release / secrete, (named) cytokine(s) ; 6. activates other immune cells ; 7. killer/cytotoxic, T cells destroy, tagged / infected, cells ; T helper cells produce cytokines that stimulate other immune cells = 3 marks Effect of HIV 8. (HIV) virus, binds to /enters/infects, T helper cells ; 9. HIV destroys T (helper), cells / lymphocytes ; 10. fewer T (helper), cells / lymphocytes ; 11. fewer B lymphocytes/ phagocytes, activated ; c i A QWC role: antigen binding ; structure: variable, amino acids/ amino acid sequence/primary structure ; (so is) specific to antigen ; 1 6 max AWARD if at least one mark is awarded from all three sections (i.e. B lymphocytes, T lymphocytes, and effect of HIV) 13

14 B role: binds to phagocyte ; structure: same/similar, amino acids/amino acid sequence/ primary structure ; (for) opsonisation ; C role: (independent) movement of variable regions ; structure: flexible ; (allow) binding to more than one antigen ; ii D = heavy (polypeptide) chain ; E = disulphide, bridge/bond ; 2 Total 22 Question Answer Marks Guidance 7 a i Mycobacterium (tuberculosis ); 1 ii 1. persistent cough / blood when coughing ; 1 max 2. fever ; 3. weight loss ; 4. tiredness ; b 1. (over) crowding increases transmission rates ; 2. lower rate of vaccination (in areas of poverty) ; 3. malnutrition weakening immunity ; 14

15 c i those in high risk areas / areas with high TB prevalence ; 1 ii different modes of transmission ; 1 max different rates of transmission ; Total 6 15

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