GCE
Biology
and Health
ora – or reverse argument
ecf – error carried forward
Any terms with a solid underline must be present to score the relevant marking point.
Any terms with a wavy underline themselves do not need to be present to score the
relevant marking point, though alternative responses need to be closely related in
meaning or be a clear description.
Marking points are separated by a semi-colon (;)
Bracketed words are not necessary to score the marking point – they are simply
there to „set the scene.
Where commas are used (,) they indicate that some information on each of the sides
of the commas are required to score the relevant marking point.
F212 Mock Paper Mark Scheme crashMATHS
Question Answer Marks Guidance
1 (a) (a balanced diet contains) all / each, of, (the) nutrients / food groups; in the correct proportions / AW;
1 ACCEPT a list of food groups that contains at least – proteins, fats, carbohydrates, vitamins, minerals IGNORE components ACCEPT right amount of
(b) (excess salt will) decrease the water potential of the blood; more water is held in the blood (by the kidneys); blood pressure increases;
2 IGNORE water concentration, unqualified ACCEPT reabsorbed ACCEPT hypertension
(c) human immunodeficiency virus; acquired immune deficiency syndrome;
2
(d) Africa have the highest prevalence of HIV / AW; Western Pacific / Eastern Mediterranean have lowest prevalence of HIV / AW; any correct comparison between the HIV prevalence in two regions; use of two sets of data correctly;
3 IGNORE high prevalence. Answers must be comparative. ACCEPT AVP, e.g. “Europe has a higher prevalence of HIV than South-East Asia”. Data must be quoted with units. See below for data
Region Western Pacific
(e) higher prevalence of HIV because… more unprotected sexual intercourse; medical equipment unsterilised / AW; more unscreened blood transfusions; less education on unprotected sexual intercourse; more overcrowding;
3
(f) less (cases of) unprotected sexual intercourse; greater awareness of HIV; improved handling of medical equipment;
1 ACCEPT relevant examples, e.g. references to education ACCEPT medical equipment sterilised
(g) (i) idea that data becomes void 1 ACCEPT relevant examples
(ii) to compare; how diseases have changed over time / AW;
2
Question Answer Marks Guidance
2 (a) (made up of) α-glucose subunits; 1-4 and 1-6 glycosidic bonds; branched; compact;
2
(b) insoluble; do not affect the water potential of the cell; do not move away, from storage regions, in
2
F212 Mock Paper Mark Scheme crashMATHS
solution; hold glucose molecules in chains; energy can be easily released when required / AW;
(c) (Jack is) wrong; colour should be purple/lilac, if protein present; sample B contains a protein;
2
(d) any three from : E1: use Benedicts test ; E2: heat sample, with Benedicts solution; to (around) 80°; E3: (if reducing sugar present) filtrate / sample, (will be) red / orange; any three from : R1: repeat test, three times; R2: use the same concentration of Benedicts solution (for each repeat); R3: heat each sample to the same temperature;
5 IGNORE references to how to take quantitative measurements.
ACCEPT Benedicts reagent
ACCEPT any temperature in the range 70 - 80° inclusive ACCEPT any named number of repeats. DO NOT CREDIT repeats alone, unqualified ACCEPT volume
F212 Mock Paper Mark Scheme crashMATHS
(e) (i) so that they do not absorb any light / AW 1
(ii) percentage transmission is, the amount of light that, passes through the solution; percentage absorption is, the amount of light that, is absorbed by the solution;
2 ACCEPT higher level answers, e.g. answers relating to wavelength and logarithms
(iii) to increase accuracy;
1 IGNORE references to colour of Benedicts solution etc.
Total 11
2 distinct classes;
OR 3 controlled by a few genes;
4 environment has very little effect / AW;
3 ACCEPT examples relevant to the data given, e.g. individual blood groups / blood groups in distinct categories If candidate suggests that this variation is not controlled by genes, the maximum mark that they can be awarded is 2 (mp 1 and 2)
(b) A1: close their stomata, when there is little water available; E1: conserves water, to prevent wilting; A2: open their stomata only at night; E2: conserves water, as less water will be lost at
5 DO NOT AWARD more than 3 A marks. IGNORE “open their stomata at night” – this marking point can only be awarded if candidates emphasise
F212 Mock Paper Mark Scheme crashMATHS
night; A3: fold or roll their leaves, when there is little water available; E3: traps a layer of moisture / air, which reduces the water vapour potential gradient; A4(a): shallow roots spread over a wide area; E4(a): allows the plant to absorb a lot of water (when available) OR A4(b): roots very long; E4(b): allows the plant to absorb water that is deep in the soil; A5: small leaves; E5: reduces the surface area for evaporation / transpiration; A6: waxy leaves; E6: prevents water loss, as water can only be lost through the stomata;
4 max QWC;
that the stomata only open at night. 1 mark if two corresponding A and E marks are awarded within the answer;
(c) (a parasite is) an organism that lives on a host; causing it harm;
2 ACCEPT another organism ACCEPT relevant example of a parasite for mp1
F212 Mock Paper Mark Scheme crashMATHS
(d) S1: warmth; E1: AVP; S2: nutrition; E2: AVP; S3: shelter / safety; E3: prevents (the parasite), being sourced out, by predators / AW;
2 ACCEPT qualified references to enzymes, metabolism or homeostasis. ACCEPT references to metabolism Only award one S mark and one E mark. The E mark must correspond to the S mark. Mark the first suggestion only.
(e) existence of silent crickets is genetic; caused by a selection pressure; silent crickets are more likely to survive, as they are less likely to be parasitized; singing crickets have a reduced chance of mating; silent crickets and singing crickets are less likely to mate, together; (as there is) less mixing of genes (between the silent and singing crickets), two different species are likely to form;
5 ACCEPT alleles for genes throughout ACCEPT as the flies are less likely to be attracted to them ACCEPT “crickets that make a noise” instead of “singing crickets”
Total 17
4 (a) hormones / antibodies / membrane carriers / membrane pores;
alpha helix;
tertiary;
4 ACCEPT examples e.g. insulin, carrier proteins, etc. IGNORE membrane proteins unqualified
(b) (i) disulphide (bonds); ionic (bonds); hydrogen (bonds); hydrophilic / hydrophobic interactions;
2
(ii) disulphide bonds are formed between two sulphur atoms; ionic bonds is formed (by the electrostatic attraction) between two oppositely charged atoms; hydrogen bonds are formed between a slightly positively charged atom and a slightly negatively charged atom; hydrophilic and hydrophobic interactions are formed in a water based environment;
2 ACCEPT between two cysteine amino acids ACCEPT between two oppositely charged amino acids ACCEPT hydrogen and oxygen as examples of slightly positively charged and slightly negative charged groups respectively
F212 Mock Paper Mark Scheme crashMATHS
(c) the catalyse enzyme has an active site, that has a specific shape, to hydrogen peroxide; when hydrogen peroxide binds to the active site, the enzyme changes shape; enzyme-substrate complex; this produces water and oxygen gas / enzyme- product complex;
2
(d) question invalid; award 1 mark in all cases 1
(e) s-1 1
(f) (i) 1 he is wrong; (up to and) at the optimum pH; 2 rate of reaction increases; 3 (because) the concentration of hydrogen ions,
gives the tertiary structure of the enzyme, the best overall shape;
beyond the optimum pH; 4 charge distribution in the active site changes; 5 hydrogen / ionic, bonds break; 6 tertiary structure / 3D shape / active site,
changes;
4 If candidate claims he is right, no marks can be scored. 1 ACCEPT partially correct only if the candidate mentions mp 2 and 7. ACCEPT H+ ions DO NOT CREDIT H ions / H- ions 5 DO NOT CREDIT in context of heat / vibrations
F212 Mock Paper Mark Scheme crashMATHS
or 6 enzyme / tertiary structure, denatures;
7 substrate, does not fit into the, active site;
8 (hence) rate of reaction decreases, beyond
the optimum pH;
6 IGNORE active site denatures
(ii) independent variable is what you change, the dependent variable is what you measure;
1 Both points are needed for the mark to be awarded. ACCEPT in context of the given experiment, independent variable is pH and dependent variable is time / rate / volume of oxygen gas produced.
(iii) C1: temperature; S1: conduct the experiment in controlled conditions; C2: enzyme / catalase concentration; S2: use a fixed volume of enzyme / catalase solution, each time; C3: substrate / hydrogen peroxide concentration; S3: use a fixed volume of substrate / hydrogen peroxide solution, each time; C4: volume of oxygen gas produced; S4: use a gas syringe, to measure the volume of oxygen produced; OR C4: time for each trial; S4: allow two minutes for each trial / AVP;
2 Mark the first response only. ACCEPT AVP to control temperature, e.g. use of a water bath etc.. IGNORE amount IGNORE amount SPECIAL CASE: If candidate gives both volume of oxygen gas and time as a control variable, apply CON and award no marks. ACCEPT any stated time
F212 Mock Paper Mark Scheme crashMATHS
(g) to increase, the reliability (of the experiment); 1 IGNORE reliability alone, reliable results unqualified Candidates must imply that repeating the experiment increases the reliability.
Total 20
Question Answer Marks Guidance
5 (a) 3 domains AND 5 kingdoms; domains are, bacteria / eubacteria, AND archaea / archaebacteria, AND eukarya / eukaryotes / eukaryotae; kingdoms are, prokaryotes AND protoctists AND fungi AND plants AND animals; eukaryotes split into different kingdoms / all eukaryotes are in the same domain; all prokaryotes are in the same kingdom / all prokaryotes are in different domains; domain classification is based on, rRNA / RNA polymerase / ribosomes / protein synthesis / enzymes / flagella / membrane structure ;
3 ACCEPT phonetic spellings throughout ACCEPT alternate names for kingdoms and domains throughout DO NOT CREDIT protists / protozoa IGNORE RNA alone unqualified DO NOT CREDIT other forms of RNA ACCEPT any given detail of protein synthesis SPECIAL CASE: If candidate states two different types of RNA, apply CON and DO NOT award the mp.
F212 Mock Paper Mark Scheme crashMATHS
(b) 1 (use of) quadrat
2 random sampling;
4 (use of an) identification key;
5 (work out) species richness;
6 (work out) species evenness;
7 use of Simpsons formula;
7 1 ACCEPT description of a quadrat / point frame 1 IGNORE quadrant 2 ACCEPT examples of random sampling, e.g.
random number generator etc
/ N value (must be upper case)
6 ACCEPT relative abundance of individual in each species / n value (must be lower case)
7 ACCEPT quoted formula
8 a high value of Simpsons diversity index, indicates a high level of biodiversity;
9 a high value of Simpsons diversity index, indicates a stable habitat;
10 a low value of Simpsons diversity index, indicates a low level of biodiversity;
11 a low value of Simpsons diversity index, indicates an unstable habitat;
11 ACCEPT examples, e.g. more susceptible to disease
6 max
QWC;
1 mark for their points between mps 1-7 given in order plus at least one of mp 9 or mp 11
Total 10
Question Answer Marks Guidance
6 (a) tar contains carcinogens; tar deposits, on the surfaces, of the lungs; these carcinogenic compounds, enter the nucleus (of the cells) in the lung tissue; (they can) have a direct effect on the genetic material of the cell OR cause a mutation;
4 ACCEPT carcinogenic compounds / named examples, e.g. benzopyrene;
(b) chronic bronchitis; emphysema; atherosclerosis; thrombosis; CHD / coronary heart disease; stroke;
2 ACCEPT phonetic spellings that begin with athero
(c) nicotine; carbon monoxide;
F212 Mock Paper Mark Scheme crashMATHS
(d) educational programmes; advertisements; informing people of the negative effects of smoking; increasing the price of cigarettes; enforcing laws / make it illegal; AVP;
2 ACCEPT AVP
7 (a) C B A; 1
(b) macrophages undergo phagocytosis; they dont fully digest the pathogen; they separate out the antigens and present them on the cell surface;
3 ACCEPT any detail of phagocytosis, e.g. engulf pathogen.
(c) plasma cells AND memory cells; plasma cells, secrete / produce antibodies; memory cells, provide immunological memory, against the pathogen;
3 IGNORE named antibodies ACCEPT memory cells preserve the antigens of the invading pathogen
F212 Mock Paper Mark Scheme crashMATHS
(d) cytokines; (work by) cell signalling; cytokines (have receptors that) have a specific / unique shape; cytokines have a complementary shape to, receptors, on the host cell; cytokines binds, to the receptors, on the host cell
3 ACCEPT interleukins for cytokines throughout. NOTE: “cytokines have a specific shape that is complementary to the receptors on the host cell” = 2 marks (mps 3 and 4) CONDONE target cell for host cell
(e) antigens on the cells appear foreign; antigens removed and presented on cell surface of engulfing cells; cells destroyed by T killer cells;
2 ACCEPT explanations in context, e.g. “in Type 1 diabetes, the antigens on the pancreatic / Islet of Langerhans / beta cells appear foreign” ACCEPT details of this process, e.g. hydrogen peroxide is released by T killer cells to destroy the cells.
Total 12