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Transcription

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2 Mark schemes (a) (i) A = cytoplasm B = (cell) membrane nucleus accept chromosome / DNA / genes accept phonetic (b) 3 [6] (a) B (b) D (c) A [3] 3 (a) (i) (cell) membrane vacuole Page of 3

3 (b) any two from: (cell) wall chloplast(s) igne chlophyll vacuole igne cell sap (c) diffusion [5] 4 (a) (i) makes / produces / synthesises protein / enzyme plant cell has nucleus / vacuole / chloplasts / chlophyll plant cell is much larger It = plant cell allow crect reference to DNA chromosomes allow plant cell has fewer ribosomes allow cellulose (cell wall) (b) (i) 00 crect answer with without wking gains marks if answer increct, allow mark f 00 bacterial cell is too small / bacterial cell about same size as a mitochondrion / no room igne references to respiration [5] 5 (a) cell division / bacterium divides / multiplies / reproduces allow asexual / mitosis igne growth (b) 8 Page 3 of 3

4 (c) (d) / / do not accept.8 /.8 04 /.8 4 allow ecf from wrong count to kill / destroy other microganisms / named type to prevent contamination igne germs / viruses to prevent other microganisms affecting the results other microganisms would be counted allow to give accurate / reliable results prevent growth of pathogens / disease-causing microganisms / dangerous microganisms do not accept microganisms become pathogenic igne germs / viruses igne general safety / biohazards / harmful products produced by bacteria (e) to improve the reliability of the investigation / check f anomalies do not accept accuracy / precision / fairness / validity igne averages / repeatability / reproducibility [7] 6 (a) (i) diffusion is down the concentration gradient f a description of diffusion igne along / across gradients to enter must go up / against the concentration gradient accept by diffusion ions would leave the root concentration higher in the root / plant concentration lower in the soil active transpt allow active uptake Page 4 of 3

5 (b) (i) (root hairs ) large surface / area (aerobic) respiration do not allow anaerobic releases / supplies / provides / gives energy accept make ATP (f active transpt) do not allow makes / produces / creates energy (iii) starch is energy source / ste (f active transpt) allow starch can be used in respiration do not allow makes / produces / creates energy [7] 7 (a) mark f each crect line mark each line from left hand box two lines from left hand box cancels mark f that box 3 Page 5 of 3

6 (b) energy [4] 8 (a) (i) tissue extra box ticked cancels the mark gan extra ring drawn cancels the mark (b) (i) Layer B Layer C each extra box ticked cancels mark (contain) chloplasts / chlophyll other parts disqualify (c) two crect = marks one crect = mark extra line from a part of a cell cancels the mark [7] Page 6 of 3

7 9 (a) because water enters (the cell / it / named cell) by osmosis / diffusion do not accept salt / sugar / solution entering if osmosis / diffusion not given accept concentration inside cell greater than outside cell assume concentration refers to solute concentration unless answer indicates otherwise allow water goes up the concentration gradient allow water goes down its concentration gradient do not accept if diffusion of salt / sugar through a partially permeable membrane allow semi / selectively permeable membrane description (b) (plant cells) have (cell) wall accept animal cells have no (cell) wall igne reference to cell membrane do not accept reference to other ganelles any implication that animal cells have a cell wall eg plant cells have a thicker cell wall [4] 0 (a) (i) release energy allow provide / supply / give energy do not accept produce / create / generate / make energy do not allow release energy f respiration contain half the (number of) chromosomes contains one set of chromosomes contains 3 chromosomes allow genetic infmation / DNA / genes / alleles instead of chromosomes accept haploid Page 7 of 3

8 (b) any two from: (stem cells) are unspecialised / undifferentiated allow description eg no particular job are able to become differentiated can fm other types of cell / tissue / gan stem cells can / able to divide / multiply [4] (a) (i) sex cells chromosomes (b) (i) two recessive (c) (i) cell membrane allow membrane cytoplasm (d) (i) A B [8] (a) root (b) (i) chlophyll absbs / traps / takes in light do not accept attracts / solar energy /sunshine / sun Page 8 of 3

9 (f) photosynthesis accept to make food / glucose / sugar/ biomass (c) mark per crect line extra line from a mineral ion cancels the mark [6] 3 (a) (i) inoculating loop V W either der (iii) Z (b) carbohydrates [5] 4 (a) (i) C and D cell wall (b) (i) A Page 9 of 3

10 D (c) respiration [5] 5 (a) B no mark f B, alone large(r) surface / area large(r) membrane accept reference to microvilli accept reasonable descriptions of the surface do not accept wall / cell wall igne villi / hairs / cilia (b) (i) any one from: insulin / hmone if named hmone / enzyme must be crect f pancreas enzyme / named enzyme many ribosomes (ribosomes) produce protein accept insulin / hmone / enzyme named is (made of) protein allow many mitochondria () provide energy to build protein to make protein () accept ATP f energy [4] 6 (a) (i) root hair Page 0 of 3

11 any two from: igne food water ions / minerals / nutrients / salts / crect named eg nitrates igne N,P,K oxygen (b) (i) stomata diffusion [5] 7 (a) (i) A cytoplasm B nucleus accept clear indications any two from: two required f mark P R T accept lower case letters (b) sperm cells need a lot of energy to swim [4] Page of 3

12 8 (a) any two from: sterilise / kill microganisms igne cleaning / disinfect igne germs method of sterilisation eg apparatus / media sterilised in oven / autoclave allow pressure cooker / boiling water pass flask mouth / pipette tip / loop / test tube mouth through flame wk near a flame minimise opening of flask / test tube hold non-vertical allow idea of sealing / covering prevent entry of air (b) any two from: temperature igne references to time / type of bacterium concentration / amount of nutrients / ions type of nutrient volume / amount of solution amount of bacteria added agitation amount of oxygen (c) (i) 7.5 accept in range use me ph values around / close to ph 7.5 / between 7 and 8 [6] Page of 3

13 9 (a) it has many chloplasts. (b) (has) cell wall (has) vacuole large / permanent vacuole do not allow chloplasts assume plant cell throughout accept converse f animal cell [3] 0 (a) A (b) (i) diffusion (iii) respiration mitochondria (iv) photosynthesis [5] Page 3 of 3

14 (a) Liast A Action List B Effect mark per crect line each extra line cancels mark (b) (i) dish has (colonies of) microganisms / bacteria / (but there are none in dish ) allow fungi / pathogens / microbes / germs allow me microganisms in dish 3 untreated milk contains living microganisms microganisms killed by UHT no living microganisms in UHT milk igne microganisms enter from the air Page 4 of 3

15 (iii) dish 3 was not opened do not allow no growth of microganisms because of lack of air / oxygen it was sterilised igne microganisms cannot enter from the air nothing / no milk was added [6] (a) root hair (b) (i) if increct unit added = 0 igne wking lack of wking accept crect answer from candidate s (i) f marks with no answer wrong answer gains mark accept ecf Page 5 of 3

16 (iii) absb me water / ions allow get / collect / take in / take up / soak up / suck up f absb allow lots f me allow moisture f water allow minerals / salts / nutrients f ions do not allow food named foods absb water / ions gains mark large surface area to absb water / ions () large surface area linked to increct function = igne small so sht diffusion pathway [6] 3 (a) A nucleus B C (cell) membrane cytoplasm (b) any two from: (contain mitochondria many (mitochondria) respiration (occurs in mitochondria) [5] 4 (a) any two from: amylase / carbohydrase protease allow trypsin lipase Page 6 of 3

17 (b) (i) high / above nmal blood sugar cannot control blood sugar allow other symptoms eg frequent / plentiful urination sugar in urine thirst weight loss coma igne consequential effects eg blood pressure / circulation / glaucoma / tiredness any one from: small / regular meals low sugar (meals) low GI / GL carbohydrates as starch allow high fibre igne reference to low carbohydrate (iii) any one from: keep constant( blood) sugar prevent high (blood) sugar reduces surge / rush of sugar into blood reduce the need f insulin (iv) (take) insulin allow pancreas transplant (c) protein / hmone / enzyme synthesis synthesis of named example combine amino acids [7] Page 7 of 3

18 5 mark f each line extra line from List A Action cancels the mark [4] 6 (a) any two from: transpt up / against concentration gradient / low to high concentration uses energy (b) use of protein / carrier microvilli large(r) surface area accept have carriers mitochondria release energy make ATP do not accept makes energy [4] 7 (a) A nucleus B (cell) membrane C cytoplasm Page 8 of 3

19 (b) (i) it is thin diffusion [5] 8 (a) (i) red cell (iii) diffusion haemoglobin (iv) a nucleus (b) (on diagram) arrow from any part of blood to air [5] 9 (a) (i) A = nucleus B = (cell) membrane (b) 70 (cell) membrane if crect answer, igne wking lack of wking f mark [5] Page 9 of 3

20 30 (a) hold cells together prevent flow of cells trap cells (b) 500 if crect answer, igne wking / lack of wking f mark igne any units (c) (i) size RBC approximately same size capillary no room f me than one cell only one can fit RBC is too big allow use of numbers do not accept capillaries are narrow me oxygen released (to tissues) me oxygen taken up (from lungs) and any two from: slows flow me time available shter distance (f exchange) close to cells / capillary wall me surface area exposed [7] 3 (a) A = nucleus accept phonetic spelling only B = (cell) membrane accept plasma membrane Page 0 of 3

21 (b) (c) any one from: photosynthesis makes sugar / starch / carbohydrate / ganic material traps absbs light any two from: accept makes food do not accept makes chlophyll igne stes starch / food / light / chlophyll Plant cell (has) vacuole has cell sap (has) wall/cellulose (stes) starch doesn't ste glycogen Animal cell no vacuole small/tempary vacuole no cell sap no wall/cellulose only membrane doesn't ste/have starch stes glycogen igne reference to shape must be clear indication in all four boxes igne reference to chlophyll [5] 3 (a) (i) haemoglobin / oxyhaemoglobin must be phonetic carries oxygen fms oxyhaemoglobin Igne references to CO / iron cancel if extras like food / glucose from lungs to tissues Page of 3

22 (b) no nucleus biconcave disc (described) igne references to size igne vague references to being round / donut shaped etc. [4] 33 (a) A cytoplasm where (chemical) reactions take place do not accept where cell functions take place carries/holds the ganelles/named ganelles / named chemicals (including nutrients) contains water do not accept keeps the shape of the cell presses out on the membrane allow: keeps cell turgid allows transpt through the cell B membrane do not accept by themselves: protects cell gives shape controls what enters/leaves the cell contains the cell/holds the cell together do not accept keeps harmful substances out allows movement into and out of the cell C nucleus Page of 3

23 contains the genetic material/dna/genes/chromosomes do not accept: brain of the cell stes infmation/instructions tells cell what to do controls (the activity) of the cell (b) (i) one mark f each crectly labelled part cell wall do not accept anything inboard of the inner edge vacuole accept anything inboard of transplant chloplast: site of photosynthesis/ f photosynthesis accept wd equation balanced equation cell wall: suppts the cell/keeps the shape/keeps it rigid do not accept protects the cells vacuole: acts as reservoir f water / chemicals/(cell)/sap 3 keeps cell turgid/pushes content to edge maintains concentration gradient allows cell elongation (not growth) [] 34 (i) the loop is sterilised accept to kill anything on the loop to kill any bacteria on it; do not credit to clean the loop if hot it would kill bacteria picked up (from culture); accept microganisms microbes accept entry of contaminated air but reject entry of air unqualified Page 3 of 3

24 (iii) to prevent entry (from the air) of unwanted bacteria bacterial spes fungal spes; accept so can t breath on it accept microganisms microbes (iv) so that the (petri) dish is not opened (after bacteria are cultured) to reduce evapation drying of the agar, accept microganisms microbes accept to prevent anything relevant getting in/out reject references to spillage [4] 35 (a) (b) award one mark f each key idea energy released energy transferred respiration allow provides gives do not allow produces makes near to the site of movement energy available quickly me energy accept allows me mitochondria to fit in (mitochondria) packed (around filament) efficient arrangement spiral arrangement contains chromosomes genes DNA not genetic material 3 (which) contribute half (the genes) to the fetus offspring 3 chromosomes half the genes reference to X,Y chromosome determining sex (if the notion of halfness is there) nucleus contains half genes f the offspring = marks [5] Page 4 of 3

25 36 (a) (i) award mark f any of the mitochondria crectly labelled if a number are labelled and one is increct award 0 marks respiration the release transfer of energy it contains the enzymes f respiration do not accept energy produced (b) (i) nucleus (named and crectly labelled) arrow line must touch go inside the nuclear membrane DNA genes nucleic acids accept protein histones nucleotides ATGC Page 5 of 3

26 (c) enzymes nucleus do not accept facts that affect the rate rather than control it eg ph temperature [5] 37 (a) mesophyll / / / / (all crect) sperm / / x / (all crect) f mark each (b) (i) absbs light/to produce food/photosynthesis (allow references to gaseous exchange) f mark has chlophyll/chloplasts to absb light/produce food f mark each (if linked to gas exchange allow moist surface/ dissolve gases) [5] 38 (i) cytoplasm (cell) membrane nucleus all crectly labelled each f mark gains marks (5/00 0 ½ / gains mark if 0.5 not given) [5] Page 6 of 3

27 39 cytoplasm reject protoplasm (cell) membrane nucleus all crectly labelled each f mark [3] 40 (a) (cell) wall (cell) membrane cytoplasm vacuole f mark each 4 (b) (i) A B f mark each (c) diffusion (reject osmosis) f mark [7] 4 (a) all required accept a 6n 6 n n 6n version of the balanced equation provided it is crect in every detail (b) any two of (presence of) chlophyll (amount of) chloplasts accept green leaves ( other green parts) (sufficient) light (intensity) (light) of a suitable wavelength any light other than green light do not credit Sun s energy sunshine Sun Page 7 of 3

28 (c) (d) guard cells any two of * control by osmosis * the movement of gases * through the stoma palisade cells any two of accept movement of carbon dioxide oxygen water vapour beware movement of CO out accept a diagram description * near the upper surface * contain (a great) many me chloplasts * (so) contain the most chlophyll any three of * f respiration * conversion to (insoluble) starch to food ste to (other)carbohydrates * (conversion to) sucrose to food ste to (other) carbohydrates polysaccharides do not credit just to grow live survive accept conversion to food ste to (other) carbohydrates once only * (conversion to) lipids fats oils * (conversion to) amino acids (plant) proteins auxins (plant) hmones enzymes 3 [0] Page 8 of 3

29 4 (a) (i) the three features crectly labelled on cheek cell (which are referred to in part nucleus cytoplasm label lines should touch end very close to part no marks if leaf cell labelled cell membrane mitochondrion accept mitochondria one of these could be labelled vacuole 3 any three from feature function nucleus cytoplasm occurs membrane chemicals controls cell accept contains genetic material genes chromosomes stes infmation do not credit the brain of the cell where respiration accept contains food mitochondria reactions occurs less water accept surrounds the cell lets some things in but not others do not credit keeps things out protection in and out mitochondria where energy released ecf from leaf cell labelling accept chloplasts make sugar glucose accept vacuole contains sap accept if cell wall mis labelled on cheek cell, suppt hold together 3 Page 9 of 3

30 (b) fight ingest kill bacteria germs viruses microbes accept produce antitoxins antibodies fight disease (ganisms) do not credit fungus (transpt) oxygen carry haemoglobin accept transpt carbon dioxide helps fm scabs [8] 43 (i) 6 in both spaces do not credit if any fmula has been altered glucose allow fructose dextrose (iii) mitochondria accept ganelles [3] 44 (a) (i) water (molecules) enter(s) (the cell) water (molecules) pass(es) through the (semi-permeable) cell membrane by osmosis because the concentration of water is greater outside (the cell than inside it the vacuole) accept because of the concentration gradient provided there is no contradiction Page 30 of 3

31 any one from (it is) elastic (it is) strong (it is fully) permeable (to water) water can pass through it do not credit semi-permeable do not credit cell membrane is semi-permeable (b) (the piece of) potato shrinks loses its turg becomes flabby becomes flaccid plasmolysis occur cytoplasm pulls away from the cell wall (because) concentration of sugar because concentration of water (solution) is greater than concentration inside the cell / vacuole inside the cell / vacuole is greater than concentration (of water) outside water is drawn out of the cell [6] 45 (a) 3 (b) chromosome nucleus gene cell 3 4 (c) (i) any one from (cells which are bigger) take up me space (cells) have to get bigger mature to divide Page 3 of 3

32 chromosomes duplicate make exact copies of self accept fms pairs of chromatids nuclei divide accept chromatids chromosomes separate identical (daughter) cells fmed accept f example, skin cells make me skin cells cells are clones (d) any two from Differentiation mark babies need are made of different types of cells cells that have different functions accept different cells are needed f different gans Division specialisation mark as fertilised egg starts to divide each cell specialises to fm a part of the body accept specialised cells make different parts of the body Growth mark specialised cells undergo mitosis to grow further cells accept cells divide reproduce to fm identical cells [8] Page 3 of 3