GCE Human Biology Unit F222: Growth, Development and Disease Advanced Subsidiary GCE Mark Scheme for June 2017 Oxford Cambridge and RSA Examinations
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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
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
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 / 76 33 3 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
(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 80-100kg ; 5. more between 40-50kg ; ACCEPT any value within the ranges for mp 3 and 4 6
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: 120 82.5 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
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
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
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
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
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
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
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
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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