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A detailed mark scheme for an ocr a level biology exam on hormonal communication. It includes answers to questions about homeostasis, insulin and glucagon, and the effects of low blood glucose on the body. The mark scheme is designed to help students prepare for their exams and understand the key concepts related to hormonal communication.
Typology: Exams
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Time Allowed: 64 minutes Score: / 53 Percentage: / Grade Boundaries: A* A B C D E U
85% 77.5% 70% 62.5% 57.5% 45% <45%
Question Answer Marks Guidance (^1) (a) (^1 idea^ of^ maintaining^ (relatively)^ stable^ internal^ , environment / state ; 2 within (narrow) limits / within (narrow) range / about a set point ; 3 even though environment is changing ; 2 max 1 Need the idea of ‘constant’ or ‘steady’ and ‘regulation’ or ‘keeping’ and in the body 2 ACCEPT about the ‘norm’ IGNORE ref to negative feedback (as mechanism rather than definition) / optimum conditions CREDIT mps 2 & 3 (only) if response is in terms of example(s) e.g. temperature / blood glucose Note ‘maintaining a stable body temperature’ = 0 ‘keeping your body temperature at 37oC’ = 1 (mp
Question Answer Marks Guidance (^1) (b) ( requires (daily) , insulin / hormone , injections ; is not affected by dietary changes ; 1 max ACCEPT insulin is not being produced in sufficient quantities (^1) (b) (i idea that has developed in , an old(er) person / middle age / a 55 year old ; 1 Mark the first answer. If the answer is correct and an additional answer is given that is incorrect or contradicts the correct answer then = 0 marks DO NOT CREDIT references to diet, as this was ineffective but use NBOD icon to indicate this Total 10
For more awesome GCSE and A level resources, visit us at www.savemyexams.co.uk/ F214 Mark Scheme June 2011 Question Expected Answer Mark Additional Guidance 2 (a) 1 less ventilation / Idea of difficulty in exhaling due to less recoil / small surface area for gaseous exchange / less oxygen entering capillaries / less oxygen entering blood ; 2 less oxygen (reaching cells) for , (aerobic) respiration / oxidative phosphorylation ; 3 (so) less ATP produced ; 4 idea of increased acidity (as CO 2 / lactate builds up) interfering with / affects , enzymes / respiratory metabolism ; 2 max IGNORE ‘ produces’ energy in any mark point 1 DO NOT CREDIT no oxygen 2 DO NOT CREDIT no respiration 3 DO NOT CREDIT no ATP 2 (b) 1 not enough / less , glucose uptake into cells ; 2 not enough / less , glucose / substrate , for , respiration / ATP production ; 3 glucose not , stored as / converted to , glycogen ; (^2) max ACCEPT ‘sugar’ for glucose IGNORE (excess) glucose lost in urine (as does not answer the Q) Only CREDIT ora if candidate clearly states that the sequence of events does not happen in this case 1 DO NOT CREDIT no glucose uptake 2 IGNORE produces energy DO NOT CREDIT no respiration / no ATP / no glucose
For more awesome GCSE and A level resources, visit us at www.savemyexams.co.uk/ F214 Mark Scheme June 2011 Question Expected Answer Mark Additional Guidance 2 (c) 1 idea of slow rate of / sluggish , blood flow or low(er) blood pressure ; 2 less / irregular amount of , oxygen (reaching cells) for , (aerobic) respiration / oxidative phosphorylation ; 3 less glucose (reaching cells) for respiration ; 4 (so) less ATP produced ; 5 idea of increased acidity (as CO 2 / lactate builds up) interfering with / affects , enzymes / respiratory metabolism ; 2 max IGNORE ‘ produces’ energy in any mark point 1 IGNORE ‘heart doesn’t beat strongly enough’ or ‘heart beat is inefficient’ IGNORE ref to volume of blood without time/rate 2 DO NOT CREDIT no oxygen / no respiration 3 IGNORE sugar DO NOT CREDIT no glucose / no respiration 4 DO NOT CREDIT no ATP
For more awesome GCSE and A level resources, visit us at www.savemyexams.co.uk/ F214 Mark Scheme June 2011 8
For more awesome GCSE and A level resources, visit us at www.savemyexams.co.uk/ F214 Mark Scheme June 2011 9
For more awesome GCSE and A level resources, visit us at www.savemyexams.co.uk/ F214 Mark Scheme June 2011 Question Expected Answer Mark Additional Guidance 3 (a) (i) islet(s) of Langerhans ; 1 Mark the first answer. If the answer is correct and an additional answer is given that is incorrect or contradicts the correct answer then = 0 marks ACCEPT and cells in islets of Langerhans DO NOT CREDIT cells in islets of Langerhans DO NOT CREDIT cells in islets of Langerhans
For more awesome GCSE and A level resources, visit us at www.savemyexams.co.uk/ F214 Mark Scheme June 2011 Question Expected Answer Mark Additional Guidance 3 (a) (ii) use ^1 use ^2 endocrine H1 hormone (s) released directly into blood ; H2 beta / β , cells , secrete / produce / release , insulin ; H3 alpha / α , cells , secrete / produce / release , glucagon ; H4 islet / and , cells , detect / monitor , blood glucose concentration ; 3 max exocrine E1 fluid / juice / secretion / enzymes , released into duct ; E2 (release triggered by) nervous / hormonal , stimulation ; E3 pancreatic secretions into , gut / small intestine / duodenum ; E4 alkaline / pH 8 / (sodium) hydrogen carbonate ; E5 containing 2 named enzyme (s) ; 3 max QWC – technical terms used appropriately with correct spelling ; 4 max 1 If endocrine and exocrine terms are muddled, then ignore endocrine and exocrine refs but only award max 2 for both sections and do not award the QWC mark. H1 DO NOT CREDIT carried / transported , in H2 ACCEPT b cells H3 ACCEPT a cells DO NOT CREDIT incorrect spelling of glucagon H4 ACCEPT a and b cells α cells and β cells secrete glucagon and insulin = 2 marks α cells and β cells secrete insulin and glucagon = 0 marks E1 IGNORE substances DO NOT CREDIT carried / transported , in E5 CREDIT 2 enzymes but no more than 1 enzyme from each bullet point lipase amylase / carbohydrase trypsin / chymotrypsin / protease / trypsinogen / chymotrypsinogen Do not award if endocrine & exocrine are muddled. Use of 3 terms from: hormone (s), beta , alpha , glucagon , islet (s), pancreatic , duodenum , enzyme (s), amylase , trypsin (ogen) / chymotrypsin (ogen) You should use the GREEN DOT to identify the QWC terms that you are crediting. Please insert a QWC symbol next to the PENCIL ICON, followed by a tick ( ) if QWC has been awarded or a cross ( 🗴 ) if QWC has not been awarded
For more awesome GCSE and A level resources, visit us at www.savemyexams.co.uk/ F214 Mark Scheme June 2011 11
For more awesome GCSE and A level resources, visit us at www.savemyexams.co.uk/ Question Expected Answers Marks Additional Guidance 4 (a) (i) 2 nd^ messenger cAMP / cyclic AMP / cyclic adenosine monophosphate ; 1 st^ messenger adrenaline / adrenalin ; 2 Mark the first answer on each prompt line. If the answer is correct and an additional answer is given that is incorrect or contradicts the correct answer then = 0 marks ACCEPT CAMP / camp DO NOT CREDIT adenine monophosphate IGNORE chemicals not named in Fig. 5. (a) (ii) 1 glycogen glucose / glycogenolysis ; 1 max 1 DO NOT CREDIT gluconeogenesis / glycogenesis (^2) by hydrolysis ; (^2) This term must be used, or a derived term. 3 correct ref to protein kinase / glycogen phosphorylase kinase (activates glycogen phosphorylase) or glycogen phosphorylase (stimulates conversion of glycogen) or inhibition of glycogen synthase (preventing glucose conversion to glycogen) ;
For more awesome GCSE and A level resources, visit us at www.savemyexams.co.uk/ Question Expected Answers Marks Additional Guidance (a) (iii) 1 2 3 4 different tissues have different (types of adrenaline) receptors ; (causing) cAMP concentration to increase or decrease ; second messenger (may be) different ; cAMP / second messenger , activates , different / other , enzymes / enzyme reactions (in different target cells) ; 2 max IGNORE reasons not related to adrenaline (as Q specifies ‘how the adrenaline molecule can cause ...’) IGNORE descriptions of stated effects in different tissues as Q asks how adrenaline causes these different effects 1 2 ACCEPT adenyl cyclase / cAMP , inhibited 3 4
For more awesome GCSE and A level resources, visit us at www.savemyexams.co.uk/ Question Expected Answer Mark Additional Guidance 5 (a) (i) (^) starch contains (only) glucose and sucrose contains , 50% glucose or glucose and fructose ; by hydrolysis , starch releases more glucose / sucrose releases less glucose ; 2 (a) (ii) (^) both starch and cellulose are (only) made of glucose ; starch , is digestible / can be broken down and cellulose , is indigestible / cannot be broken down ; (named) enzyme present for starch digestion / no (named) enzyme present for cellulose digestion ; 2 max (b) (^1) low / decrease , starch ; as starch has the greatest effect on blood glucose conc. ; increase / include , cellulose / fibre / roughage / fat / protein / meat , as no effect on blood glucose ; some / medium amount of , sugars / sucrose / lactose ; idea of limiting , sucrose / lactose / fat / protein , as causes an increase in insulin and will make cells less responsive (to insulin) ; 1 ACCEPT ‘no starch’ (^2) 2 ‘substantial’ or ‘high’ or ‘big’ is not quite enough 3 3 IGNORE the idea that , fat / protein , increases insulin and could indirectly lower blood glucose (as this is not relevant to Type 2 diabetes) DO NOT CREDIT little effect / less effect (as table shows no effect) 4 5 3 max
For more awesome GCSE and A level resources, visit us at www.savemyexams.co.uk/ Question Expected Answer Mark Additional Guidance (c) Award one mark per row both glycogen and glucagon ; IGNORE polymer or macromolecule unless qualified glycogen DO NOT CREDIT complex sugar / sugar both glycogen and glucagon Look for qualification of glycogenolysis ; glycogen ACCEPT muscle / brain ; glucagon ACCEPT ‘a cells’ IGNORE pancrease 3 DO NOT CREDIT beta / , cells Total [10] glycogen glucagon hormone type of compoun d carbohydrate OR polysaccharide
polypeptide OR protein binds to cell receptor role of compoun d storage OR to provide glucose (when blood glucose conc. falls) OR can undergo glycogenolysi s
causes conversion of glycogen to glucose OR stimulates glycogenolysi s OR increases (blood) glucose concentration pancreas liver OR
