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GENERAL CERTIFICATE OF SECONDARY EDUCATION TYSTYSGRIF GYFFREDINOL ADDYSG UWCHRADD

MARKING SCHEME

BIOLOGY SCIENCE UNIT B1 ADDITIONAL SCIENCE UNIT B2 JANUARY 2009

INTRODUCTION The marking schemes which follow were those used by WJEC for the January 2009 examination in GCSE Biology Units B1 & B2. They were finalised after detailed discussion at examiners' conferences by all the examiners involved in the assessment. The conferences were held shortly after the papers were taken so that reference could be made to the full range of candidates' responses, with photocopied scripts forming the basis of discussion. The aim of the conferences was to ensure that the marking schemes were interpreted and applied in the same way by all examiners. It is hoped that this information will be of assistance to centres but it is recognised at the same time that, without the benefit of participation in the examiners' conferences, teachers may have different views on certain matters of detail or interpretation. WJEC regrets that it cannot enter into any discussion or correspondence about these marking schemes.

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B1 JANUARY 2009

FOUNDATION TIER

1. (a) greenfly, [1] (b) (i) compete for food; [1] (ii) eat them [1] (not: ref. to size/eat all their food)) (c) all plots correct, +/- 0.5 small square, no extrapolation, -1 per error [2] plots joined through centre of plots with a ruler [1] (d) extinct [1]

Question total [7] 2. (a) (i) 270 [1] (ii) 2630 [1] (b) (i) fat (not: cream) [1] (ii) skimmed (not: low fat) [1] (c) (i) less sugar and more calcium (in milk) [2] (not: acids/ref. to bones)

Question total [6] 3. inherits; genes; nucleus; dominant; mutation [5] Question total [5] 4. (a) Suspect B; [1] (b) The DNA/ bands match with/identical to the sample at the crime scene [1] (not: similar/fingerprints match) (c) Identical twins [1] Question total [3] 5. (a) (i) increases (not: goes up and then down) [1] (ii) increases [1] (b) (i) after the insulin level goes up, the glucose level drops. [1] (not: ref. to injection) (ii) person is asleep so not eating [1] (c) (i) Glucose level would drop too/very low [1] (not: ref. coma/no sugar) (ii) Eat or drink glucose / carbohydrate/ glucagon pen [1] (not: ref. fat/increase sugar level) Question total [6] 6. (a) nose, skin, tongue, ear. [4] (i) reflex [1] (ii) fast / automatic / protective – any 2 [2] (iii) Electrical (not: electric) [1] Question total [8]

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FOUNDATION AND HIGHER TIER 7/1 (a) (i) Genus / are the same genus / Both have the genus name Mustela [1] (ii) Because the scientific name is the same in all countries / universal / [1] the common name differs in different countries (not: global language) (b) (i) Because the stoat also hunts in farmland / ORA [1] Because the stoat can also hunt in the day / ORA [1] (ii) Because the weasel is small enough to hunt burrowing mammals /

ORA [1] (not: ref. size unqual./smaller so can hide from predators) (c) To camouflage it in the snow (from predators / prey) [1] Question total [6] 8/2 (a) (i) Tally Total – all 4 correct [1] 3, 14, 7, 2 (ii) 1 mark awarded for the quality of the chart and 1 for accuracy of the plotting

All 4 bars in correct order and correct height ± 0.5 small square with labels or key [1]

Bars drawn with clean lines, drawn with a ruler and with approximately the correct width [1] (iii) I. That the level of pollution in the stream is falling / [1] stream becoming cleaner Comparative statements needed. (Do not accept references to the number of indicators in this part of the answer, e.g. the number of ‘clean’ indicator species is increasing will not be credited here.) II. 1 mark each for any 2 from: [2] The no. of mayfly nymphs are increasing The no. of caddis fly nymphs are increasing The no. of water lice are decreasing The no. of sludgeworms are decreasing Number of indicator species in clean water have increased (The candidates may attempt to link the evidence to the stream becoming cleaner or less polluted but in order to gain the 2 marks 2 of the above 4 statements must be clearly evident) I and II – independent marks

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(b) Ref. to any two of: [2] the survey being carried out at the same time every year the exact same 10m/certain part of stream surveyed water conditions must be (as far as possible) the same e.g. temp (1), flow

rate (1) some sampling techniques must be used/same time same equipment used – specified e.g. net Not same sampler! (Ref to reliability are not to be credited) (c) oxygen / pH / heavy metals/nitrate/phosphate/pesticide [1] Question total [9]

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HIGHER TIER 3. (a) (i) HH and hh both required [1] (not: if other letters used; allow consequential error) (ii) 1 mark for all 4 gametes correct. 1 mark for mechanics of cross [2] Independent marks

Gametes H H

h Hh Hh

h Hh Hh

(not: single in a(i) and double in table or if a(i) blank) (iii) 1 mark for all 4 gametes correct. 1 mark for mechanics of cross [2] (allow consequential error)

Gametes H h

H HH Hh

h Hh hh

(iv) 20% [1] (b) transfer herbicide resistant gene [1] Question total [7] 4. (a) difference between organisms / individuals of the same species / kind [1] (b) (i) e.g. height / mass / skin / hair colour / leaf size/eye colour/ height etc. [1] (ii) e.g. tongue rolling / blood group/ gender/height of peas [1] Question total [3] 5. Less smoking now/people trying to give up/ref. helplines/smoking socially

unacceptable; Less advertising now / sponsorship/warnings on packets/under counter sales; Smoking-free zones imposed by law/ ban in public places; Ref to nicotine causes addiction; One named smoking related disease; Dangers of smoking now recognised / relate to asthma/doesn’t cure diseases. [4 × 1]

(Any 4 from 6)

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6. (a) (As the temperature rises) sweat production increases [1] urine production decrease [1] or ref to numbers (b) Explanation (As temperature rises) the sweat glands make more sweat [1] to cool the body [1]

(c) (i) hairs lie flat vasodilation occurs/capillaries increase in diameter (not: get bigger/expand/move up/ref. to shivering) [2]

(ii) Converse of c(i) (allow ref. to shivering) [2]

7. (a) (i) Heat / high temperature [1] (ii) Skin / temperature sensor [1] (not: finger/nerve endings) (iii) Spinal cord [1] (not: CNS/brain) (iv) Muscle [1] (b) Fast / speed / rapid etc [1] Automatic / unconscious/involuntary [1] 8. (a) Fossils [1] (b) Makes (skeleton) light weight (for flying) [1] (not: helps them to fly/ref. insulation) (c) Shows features of birds and reptiles/description e.g. has teeth and wings [1] Reptile remains pre-date bird remains / Reptile remains found in rocks older than rocks in which birds remains are

found / or ref to actual numbers of years [1] (d) Air spaces an advantage [1] Genes passed on (to future generations) [1] reference to mutation occurring [1]

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ADDITIONAL SCIENCE

B2 JANUARY 2008

FOUNDATION TIER 1. (a) 60% (18 million tonnes) [1] (b) less (air) pollution / less energy needed / less trees cut down or used [2] (c) non biodegradable / do not rot / decompose [1] (not: ref. to time if short term/hard to decompose/ref. to animals) Question total [4] 2. (a) (i) A – oesophagus / gullet B – stomach C – small intestine/ileum D – large intestine/colon [4] (b) insoluble plus soluble, enzymes, absorbed, small intestine [4x1] Question total [8] 3. (a) (i) respiration [1] (ii) heat [1] (b) glucose (sugar) [1] oxygen [1] (c) diffusion [1] Question total [5] 4. (a) water [1] oxygen [1] (b) chloroplasts [1] (c) (i) all plots correct - +/- 0.5 small square [2] -1 per error, including extrapolation to 0 Plots joined with a ruler through the centre of the plots (no marks if bar chart) [1] (ii) from candidates graph (39) +/- 0.5 small square [1] (iii) as light intensity increases so does (rate of) photosynthesis or opp. [1] levels off (after 160) [1] (not: ref. bubbles) (iv) temperature / CO2 /pH [1] (not: water) Question total [10]

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5. (a) (i) Clockwise – burning, respiration, feeding, photosynthesis [4 × 1] (b) bacteria / fungi / decomposers [1] (not: microbes/worms) (c) deforestation / increase burning fossil fuels / increase in traffic / increase in power stations [1] (not: cutting down trees) (d) (i) killing fish / trees/ tops of pine trees turn yellow [1] (ii) lung disease [1] Question total [8]

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FOUNDATION AND HIGHER TIER 6/1. (a) any two of the following: eaten/killed by rat / stoat Its food is eaten by possum / deer / rabbit [2 × 1] (not: competition unqual.) (b) biological [1] (not: bio control/biological pesticides) (c) easier to remove all the predators / no predators/not as many rats [1] easier to remove the animals that were competing for food / no competitors [1] (not: ref. to humans/less food unqual./closer so can breed) (d) agriculture / building / quarrying / dumping/deforestation/logging/hunting [1] (not: cutting down trees/egg collecting/habitat destruction/ref. pesticides) (e) CITES, captive breeding programmes, sperm / DNA banks / seed

banks/cloning [1] (not: zoos unqual./animal parks/nature reserves/breeding kakapo) Question total [7] 7/2. (a) (i) for a good quality drawing clearly showing a plant cell [1] (award no marks if the drawing is poorly drawn, has major features such as the cell wall missing or if the drawing is ambiguous i.e. you cannot tell whether it is a plant or animal cell) Cell wall with double line and in proportion, vacuole, nucleus and

chloroplasts in cytoplasm. (ii) 1 mark each for chloroplast, cell wall, (sap) vacuole. [3] Part (ii) is to be marked independently of part (i) Labels shared between both types of cell cancel out plant cell only labels. 8/3 (a) undifferentiated cells [1] (not: blank cell/unprogrammed cell) that have the ability to change into different types of cells [1] (not: adapt) (b) (i) will grow / change / become / repair heart / heart tissue / heart muscle [1] (ii) because the cells belong to the patient / because embryo stem cells are not being used/ ref. other animals [1] (not: ref.to not harming anybody/another innocent life) Question total [8]

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HIGHER TIER 4 (a) bacteria and fungi 1 mark each [2] (allow: decomposers for 1 mark, no mark for bacteria/fungi as well) (b) (i) Respiration 2 [1] Combustion 1 [1] Photosynthesis 3 [1] (ii) feeding/ingestion [1] (not: digestion/food chain/nutrition) Question total [6] 5 (a) (i) because badgers could move into the area/new areas (to fill vacant

niches) / because of the movement of cattle between herds/one farm to

another. [1] (ii) because it would remove a possible source of the infection in

cattle/cattle can be infected by badgers. [1] (b) badgers are protected by law / they consider the evidence is unreliable/culling

doesn’t control bTB/farmers could do more to protect their herds vaccination/ref. animal rights or inhumane [1]

(not: ref. endangered species/extinction of badgers/cruelty) (c) vaccination / more reliable (tuberculin) testing /check cattle when sold/ more

control on cattle movement/culling infected herds. [1] (not: killing cattle) Question total [4] 6. (a) water passed out; down gradient / from where water was in high concentration to where it was in low concentration; by osmosis; through S.P.M. [3] [Any 3] (b) (i) 60 [1] (ii) Least/smallest change in mass [1] (c) (i) Evaporation (of water) prevented / No change in concentration of solution [1] (not: evaporation of solution/ref. spillage) (ii) (II) [1] (iii) Repetition/use same volume of solution in each Petri dish/same

temperature (not: same variety/mass of potato) [1] (d) Boiling destroys S.P.M. / cell membrane [1] (not: killing cells) Question total [9]

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7. (a) (i) Aerobic respiration [1] (ii) CO2 / water [1] (b) (i) Slow release of / store of energy [1] (ii) Rapid / immediate release of energy [1] (c) (i) Lactic acid [1] (ii) Lack of/little oxygen / oxygen debt / anaerobic respiration [2] [Any 2] Question total [7] 8. (a) (No cost) for maintaining temperature / light./ No removal of waste

needed/natural supply of food available. [Any 2] (not: ref. disease/time and care) (b) Growth of algae/plants/algal bloom; Decay of algae (or similar wording)/waste food digested/used by

bacteria/decomposers; Oxygen used by decomposers / bacteria; For respiration; (not: breathing) Animals / fish die through lack of oxygen [Any 4] (c) (i) Bioaccumulation (description of ) [1] may kill variety of animals/decrease biodiversity [1] (ii) Reference to mussels and pesticides being eaten by humans

/pesticides get into food chain. [1] Question total [9] GCSE Biology Marking Scheme (January 2009)/ED 23 February 1009

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