F214 Communication, Homeostasis & Energy

Size: px

Start display at page:

Download "F214 Communication, Homeostasis & Energy"

Julianna Hall
5 years ago
Views:

1 F Communication, Homeostasis & Energy (a) excretion secretion One mark per row. one difference (metabolic) waste toxin / harmful substance is to be removed from body does not use vesicles useful product used in cell communication (e.g. to target tissues) released from glands (ducts ductless) uses vesicles remain in body ; CREDIT converse statements on either side unmatched statements f each IGNORE name type of product without qualification DO NOT CREDIT any ref to egestion in excretion one example of a product urea / carbon dioxide / water / bile pigment / named example hmone / enzyme / antibodies / mucus / bile salts / neurotransmitter / named example ; IGNORE sweat / urine / bile / saliva / salt / (named) digestive juice 7

2 one similarity requires ATP (involved in) homeostasis (compounds) produced by cell(s) / produced by metabolism / need to cross membrane / need to move through membrane / need to leave cell / (may be) transpted in blood ; CREDIT method of leaving cell e.g. exocytosis IGNORE going into cells (as some excrety products do) 8

3 (b) S & C Mark the first answer. If the answer is crect and an additional answer is given that is increct contradicts the crect answer then = 0 marks CREDIT one statement and a suitable explanation related to that (first) given statement (e.g. S + E but not S + E) DO NOT AWARD marks f statements explanations S E glucose is not the only substrate / there are other substrates ; named alternative substrate ; fats can (also) be respired = E fats can be respired as well as glucose = S + E S E ATP is produced / energy is released ; (by) substrate level / oxidative, phosphylation ; S DO NOT CREDIT energy produced / made / created S E ATP / energy, required ; (f) phosphylation / glycolysis ; S E is not a single step reaction / other steps involved / other products / other intermediates ; named stage(s) / named intermediate compound(s) ; E Krebs cycle / ETC, happens = E other stages such as link reaction are involved = S + E e.g. pyruvate / acetyl CoA / acetate IGNORE NAD(H) / FAD(H) / ATP S E enzymes are involved ; dehydrogenation / decarboxylation / oxidative phosphylation / named (respiraty) enzyme ; S6 E6 coenzymes / NAD, involved ; oxidative phosphylation / link reaction / Krebs cycle / glycolysis ; S6 DO NOT CREDIT NADP S7 E7 glucose does not, combine / react, (directly) with oxygen ; (oxygen) used in oxidative phosphylation / is final electron accept / is final hydrogen accept ; 9

4 (c) (i) Max if referring to insulin recepts (c) (ii) unable to produce (enough) insulin / do not secrete insulin / produces ineffective insulin ; insulin-producing cells / beta cells / islets of Langerhans, not functioning (crectly) / damaged / destroyed / attacked ; by (body s own) immune system / by (body s own) antibodies / auto-immune disease ; (idea of) family histy / genetic / hereditary ; (condition can be) triggered by, virus / environmental fact ; increasing age / older / ageing / me prevalent over 0 ; (idea of) family histy / genetic / hereditary ; (me common in) males ; (me common in) some ethnic groups / African / Afro-Caribbean / Asian / Hispanic / Oceanic ; obese / overweight / fat around abdomen ; high / frequent, intake of, sugar / highly processed food / high GI food ; lack of physical activity / sedentary lifestyle ; high blood pressure ; excessive alcohol intake ; 0 max max Total 0 DO NOT CREDIT excrete as increct ALLOW lack of beta cells / ref to b cells DO NOT CREDIT alpha cells / B cells (if lymphocytes implied) CREDIT description e.g. shock drugs side effect (pancreatic) cancer infection / disease Mark the first responses only DO NOT CREDIT age without older implication CREDIT apple shaped IGNORE po diet / bad diet / unhealthy diet IGNORE fat / carbohydrate, in diet CREDIT histy of, heart attack / stroke idea of too much is needed

5 (a) (i) Mark the first answer. If the answer is crect and an additional answer is given that is increct contradicts the crect answer then = 0 marks glycolysis / glycolytic pathway ; CREDIT phonetic spelling but must have glycol... (a) (ii) Mark the first answer. If the answer is crect and an additional answer is given that is increct contradicts the crect answer then = 0 marks cytoplasm ; CREDIT cytosol DO NOT CREDIT cytoplasm, in / of, mitochondrion (a) (iii) Mark the first answer f each letter. If the answer is crect and an additional answer is given that is increct contradicts the crect answer then = 0 mark D ATP ; E NAD ; F pyruvate ; E F ALLOW oxidised NAD DO NOT CREDIT NADP / reduced NAD ACCEPT pyruvic acid

6 (b) Award marks from labelled / annotated diagrams but ensure that mp only awarded if H clearly shown to be accepted by pyruvate (pyruvate / F) converted to lactate ; ACCEPT lactic acid DO NOT CREDIT if pyruvate ethanol in the animal is indicated/implied DO NOT CREDIT wrong reaction type (e.g. oxidation) F / pyruvate, accepts hydrogen (atoms) ; ACCEPT pyruvic acid DO NOT CREDIT hydrogen ions (unless also e - ) / molecules hydrogen from, reduced NAD / reduced E ; (catalysed by) lactate dehydrogenase ; ACCEPT NADH / NADH / NADH + H + f pyruvate lactate ACCEPT LDH 6 no, oxygen / O, to act as (final), hydrogen / electron, accept ; (so) link reaction / Krebs cycle / ETC, cannot take place ; 6 Needs a clear statement of not taking place CREDIT no, electron transpt chain / electron carrier chain / chemiosmosis / oxidative phosphylation 7 8 NAD / E, regenerated / recycled / able to be re-used ; allows glycolysis to continue / pyruvate continues to be made ; 7 8 IGNORE reduced NAD, oxidised / reoxidised (as this does not give the idea of reusing it) Needs a clear statement 9 limited / small amount of / some, ATP can be produced ; max 9 CREDIT ATP (per pyruvate) / ATP (rather than 8-8 per glucose) / only substrate level phosphylation IGNORE enough ATP f...

7 (c) physical (probably from diagrams) large nostrils (open) to take in air ; S & C ACCEPT oxygen (when submerged) nostrils close / nose closes, to, keep air in / stop air from escaping ; ACCEPT oxygen IGNORE ref to keeping water out lungs / airways, have high (vital) capacity ; links to respiration idea that seal, has low(er) metabolic rate / has low(er) respiraty rate / has low(er) energy requirements / uses (relatively) little ATP ; ACCEPT deep / barrel / large, chest IGNORE big lungs CREDIT large lung volume / takes in large volume of oxygen / larger numbers of alveoli / larger (exchange) surface area / increased number of capillaries e.g. (streamlined, less resistance so) uses less energy (insulated so retain heat so) uses less energy (buoyant so) less energy required (small flippers so less surface area of extremity so loses less heat so) uses less energy able to respire anaerobically f a long time / me glycolysis ; large supplies of NAD (to accept H) ; (this) prevents, build-up of lactate / lowering of ph ; idea that (seal) tolerates lactate / removes lactate quickly ; idea that (seal) tolerates high CO concentration ; idea that (seal) tolerates low ph / has me ph buffers ; synoptic / inference idea that blood diverted from certain regions / certain regions have reduced metabolic activity ; idea that has plenty of, haemoglobin / red blood cells / myoglobin (as oxygen source) ; idea that haemoglobin has a higher affinity f oxygen / dissociates less readily / dissociation curve shifted to left ; max Total 7 8 anaerobic needs time ref ACCEPT lactic acid ACCEPT lactic acid DO NOT CREDIT zero respiration rate

8 (a) myelin / myelinated / lipid / fatty (sheath) ; (Schwann) cell, wrapped around / surrounds / AW, axon ; except at nodes of Ranvier / (sheath) not continuous / presence of gaps (in the sheath) ; max DO NOT CREDIT fatty acids must be in the context of structure rather than function (as many refer to it in context of saltaty conduction) (b) (i) (myelination produces) greater speeds ; unmyelinated needs larger diameter to produce same speed ; comparative figs, all with units, to suppt either the general trend the exception to the trend with the mollusc ; max IGNORE ref to axon diameter f this mp speed f myelinated ( / 0 /, m s - ) and speed f unmyelinated ( / 0, m s - ) (allow m/s) calculated difference in speed between myelinated and unmyelinated (with units unless a multiple e.g. approx. x) (b) (ii) larger axon diameter produces greater speeds ; a comparative figs, all with units, to suppt ; needs to be a general statement diameters & speeds (both with units) f myelinated calculated difference in diameter f stated speeds (both with units unless diameter is a multiple e.g. around x. / around 0%) type of neurone diameter (µm) speed (m s - ) animal taxon myelinated mammal myelinated 0 0 amphibian myelinated amphibian diameters & speeds (both with units) f unmyelinated calculated difference in diameter f stated speeds (both with units unless diameter is a multiple e.g. about x0) type of neurone diameter (µm) speed (m s - ) animal taxon unmyelinated mammal max unmyelinated mollusc

9 (c) (i) increased kinetic energy / KE so, S & C ions diffuse, across (axon) membrane / into neurone / into cell / between nodes / along neurone, me quickly faster movement of (neurotransmitter) vesicles / exocytosis (of neurotransmitter) neurotransmitter diffuses me quickly across, synapse / synaptic cleft neurotransmitter (ACh) broken down by enzyme (acetylcholinesterase) me quickly ; description of ion movement must be crect (e.g. Na + in f depolarisation / Ca + into presynaptic knob) faster diffusion of ions leads to, faster depolarisation shter duration of action potential shter refracty period faster repolarisation ; max (c) (ii) DO NOT CREDIT general denaturation of proteins / enzymes ion, channels / pumps, disrupted / denatured / no longer function ; fluidity of, membrane / phospholipid / bilayer, disrupted ; (named) synaptic enzymes denatured ; IGNORE leaky membrane unless qualified max

10 (d) calcium channels open ; IGNORE ref to influx of Na + and events when action potential arrives at the synaptic knob start when the Ca + channels open Ca + / Ca ++ / calcium ions, enter / diffuse into, acetylcholine / ACh / neurotransmitter, in vesicle(s) ; DO NOT CREDIT calcium alone DO NOT CREDIT Ca + DO NOT CREDIT enter membrane must cross it 6 (synaptic) vesicles move towards presynaptic membrane ; vesicles fuse with membrane ; release acetylcholine, by exocytosis, into synaptic cleft ; max CREDIT pre-synaptic DO NOT CREDIT attach / bind / join vesicles move and fuse with presynaptic membrane = mps & vesicles move and fuse with membrane = mp only QWC technical terms used appropriately and spelt crectly ; Use of three terms from: channel(s), neurotransmitter, exocytosis, vesicle(s), presynaptic / pre-synaptic, cleft, Total 6

11 (a) (i) Mark the first answer. If the answer is crect and an additional answer is given that is increct contradicts the crect answer then = 0 marks ultrafiltration ; This term required but ACCEPT phonetic spelling (a) (ii) 7.9 ; ; Crect answer = marks If answer increct, not rounded increctly rounded then allow mark f wking 700 an unrounded answer e.g (b) (i) Mark the first answer. If the answer is crect and an additional answer is given that is increct contradicts the crect answer then = 0 marks (b) (ii) (cuboidal) epithelium / epithelial ; DO NOT CREDIT epithelium cells / ciliated epithelium / squamous epithelium / endothelium ALLOW columnar epithelium Mark the first answer. If the answer is crect and an additional answer is given that is increct contradicts the crect answer then = 0 marks microvilli / microvillus ; ACCEPT brush bder DO NOT CREDIT cilia 7

12 (b) (iii) This is a QWC question selective reabsption ; of glucose and amino acids ; co-transpt / facilitated diffusion / uptake described ; S & C DO NOT CREDIT if glucose & amino acids & proteins ACCEPT direct uptake, of glucose / amino acids, by active transpt water follows by osmosis so concentration of, ions / nitrogenous waste / urea / remaining substances, increases ; AVP ; max QWC - technical terms used appropriately and spelt crectly ; Use of three terms from: reabsption ( derived term), co-transpt ( derived term), facilitated diffusion, osmosis e.g. microvilli provide large surface area f uptake many mitochondria provide energy f uptake many brush bder enzymes (ATPase) f active uptake active secretion of nitrogenous waste into lumen 8

13 (c) (i) L artery / shunt / vein (at arterial end of shunt) AND M vein ; IGNORE names of artery / vein (e.g. renal) DO NOT CREDIT ata and vena cava (c) (ii) so that clots don t fm, while in the (dialysis) machine / during dialysis ; ALLOW congeal instead of clot IGNORE prevents clotting in the body IGNORE clumping (c) (iii) idea of allowing blood to clot nmally after treatment ; CREDIT preventing low blood pressure (as low viscosity) (c) (iv) (simple) diffusion ; (c) (v) idea that it, maintains diffusion gradient / maintains concentration gradient / maximises diffusion gradient / maximises concentration gradient / allows maximum removal of waste / allows maximum rate of diffusion / AW ; Mark the first answer. If the answer is crect and an additional answer is given that is increct contradicts the crect answer then = 0 marks IGNORE dialysis DO NOT CREDIT facilitated diffusion IGNORE unqualified ref to countercurrent e.g. solutions in contact over greater distance provides maximum contact f exchange allows exchange over longer distance Total IGNORE ref to surface area 9

14 (a) (i) control ; CREDIT a description e.g. comparison to compare results with to show that (wavelengths of) light is producing the effect to show the result produced without light create baseline create set point validity IGNORE fair test DO NOT CREDIT control variable / controlled variable 0

GCE. Biology. Mark Scheme for the Units. January 2010 HX21/MS/R/10J. Advanced GCE A2 H421 Advanced Subsidiary GCE AS H021 PMT

GCE. Biology. Mark Scheme for the Units. January 2010 HX21/MS/R/10J. Advanced GCE A2 H421 Advanced Subsidiary GCE AS H021 PMT GCE Biology Advanced GCE A H Advanced Subsidiary GCE AS H0 Mark Scheme f the Units January 00 HX/MS/R/0J Oxfd Cambridge and RSA Examinations F Mark Scheme January 00 F Communication, Homeostasis & Energy