T3W6 [USS] S4 BIO PRELIMS 2023 P1 P2 MS

S4E BIOLOGY USS Prelim Exam 2023 Mark Scheme P1 P2 Page 1 of 7 UNITY SECONDARY SCHOOL PRELIMINARY EXAMINATION 2023 Secondary 4 (Express) Biology 6093 General notes Symbols used in mark scheme and notes. 1. ; separates points for the award of a mark 2. / separates alternatives for a marking point 3. R reject 4. A accept (for answers correctly cued by the question) 5. Ig ignore/irrelevant (for incorrect but irrelevant responses) 6. AW alternative wording (where responses vary more than usual) 7. AVP alternative valid point (where greater than usual variety of responses is expected) 8. ORA or reverse argument/reasoning 9. OWTTE or words to that effect 10. ( ) contents in brackets are not required to gain marks but should be implied 11. underlined words – actual word underlined must be used by students 12. + statements on both sides of the ‘+’ are needed for that mark 13. MP mark point (numbered marking points to facilitate teaching and feedback for students) Biology 6093/01 Multiple Choice Qn C3R Ans Qn C3R Ans Qn C3R Ans Qn C3R Ans 1. KU B D 11. KU B B 21. HISP B D 31. KU B A 2. KU C B 12. KU B C 22. HISP B B 32. KU B C 3. KU C A 13. HISP B A 23. HISP B C 33. HISP A D 4. KU B C 14. KU B A 24. KU B B 34. KU B A 5. KU B D 15. KU B B 25. HISP A C 35. KU B B 6. KU B C 16. HISP B D 26. HISP A D 36. KU B A 7. KU B D 17. HISP B C 27. HISP B D 37. KU B C 8. KU C D 18. KU B A 28. KU B C 38. KU B B 9. KU B B 19. HISP B C 29. HISP B C 39. KU B C 10. KU B B 20. KU B A 30. KU B B 40. KU B C

S4E BIOLOGY USS Prelim Exam 2023 Mark Scheme P1 P2 Page 2 of 7 Biology 6093/02 – Structured and Free Response Questions Question C3R Answer Part Marks Marker’s Annotations 1a HISP A MP1. species B lost more water than species A in, either/ both, conditions/ ORA; MP2. both species lost more water in hot conditions than in cool/ ORA; MP3. the difference in water loss (in cool and hot temperature) was greater in species A compared to B/ ORA; MP4. ref data, comparison/ quote + units, for, cool/ hot; max 3 Comparison qn – expected to use ‘comparison words’ and ref species + temp Different ways of saying the same point will not get additional marks MP4 - Repeated reference to data without comparison max 1m 1b HISP A MP1. one bar drawn on Fig. 1.1, with a height less than 4.8 cm3 per hour (i.e. lower than Species B, cool temp bar); MP2. correct spacing of 2 units + same width with existing bars (cool temp) 1 1 1c KU C xylem; 1 Total: 6 2a HISP B B: cilia + (beat dust-trapped) mucus upwards/ out of the airway; C: mucus + traps particles/ pathogens; E: cartilage/ c-shaped ring + keeps the airway/ trachea open; max 3 AVP - B/C prevent infections; 2bi KU B U → P; → T → S → Q → R; V 2 2bii KU B MP1. For gas exchange/ diffusion / movement of CO2 and O2 ; MP2. short distance (for diffusion/ gas exchange); MP3. fast/ efficient (gas exchange / diffusion); max 2 Total: 7 3a HISP B kidney; 1 No ecf 3b HISP B C – renal artery; E – pulmonary artery; 2 A: aorta (C)

S4E BIOLOGY USS Prelim Exam 2023 Mark Scheme P1 P2 Page 3 of 7 Question C3R Answer Part Marks Marker’s Annotations 3c HISP B C (renal artery) F (ureter) blood + Urine; (a named) cell/ platelets/ plasma + no cells/ platelets/ plasma; proteins/ antibodies/ amino acids/ fats + none; glucose + no glucose; lower urea concentration / higher urea concentration; less salts/ ions/ less water / more salts/ ions/ water; more hormones/ vitamins / fewer hormones/ vitamins; max 4 Total: 7 Ig: ref to oxygen/ carbon dioxide waste products Ig: minerals / nutrients 4a HISP B 30; 5; 15; 0 / 30; 1m each Total: 4 5a HISP A parental phenotypes: resistant x not resistant MP1. resistant parental genotypes: Rr x rr; MP2. gametes: R, r x r, r; MP3. show working: arrows rep fertilisation; MP4. offspring genotype: Rr, Rr and rr, rr; MP5. offspring phenotype: disease resistant, disease resistant, not disease resistant, not disease resistant (1:1) 5 No ecf 5b HISP A MP1. Heterozygous plant/parent, carry the not-resistant/ r, allele; MP2. some offspring would be not-resistant/ rr/ homozygous recessive; MP3. using heterozygotes results in profit loss / AW ; max 2 5ci HISP A MP1. paint pollen onto selected trees / AW ; MP2. isolate plants / cover flowers, of unselected trees ; MP3. identify not disease resistant trees ; MP4. remove not-resistant trees max 1 A: artificial pollination 5cii KU B Artificial selection vs Natural Selection MP1. human choice vs environmental pressures) / AW; MP2. less diversity/ variation vs more variation; MP3. faster change vs slower (random); max 2 Total: 10 AVP: e.g. mating is not random Matched point by point. Merely describing each does not bring out key difference.

S4E BIOLOGY USS Prelim Exam 2023 Mark Scheme P1 P2 Page 4 of 7 Question C3R Answer Part Marks Marker’s Annotations 6a KU C MP1. unit of inheritance / give characteristics / traits; MP2. section of DNA; can be copied; MP3. (each) specifies production of one protein / polypeptide; max 2 A: contains hereditary information R: ref to chromosomes 6b KU B MP1. radiation/ x-ray/ ultraviolet; MP2. chemicals/ mutagens; MP3. faulty cell division; max 2 A: ref to smoking/ alcohol consumption can expose cells to mutagenic substances/ induce changes in DNA Ig: inherited mutations 6c HISP B MP1. reduction in surface area / volume ; MP2. so less haemoglobin; MP3. less oxygen + carriage / absorption / in blood (cell); MP4. loss of elasticity + more difficult to move through blood vessels; MP5. sticky + may clump together / clot; MP6. (causing) blockage of blood vessel + reduction of blood flow (to tissue); max 4 Total: 8 7a HISP A MP1. transport/ AW; MP2. processing/ packaging; MP3. refrigeration; MP4. cooking/ AW; MP5. waste food / disposal of low-quality food / decomposition / respiration AW; MP6. burning / combustion; MP7. fuel; max 3 7bi HISP A 27.0 – 1.1 / 27.0 = 96% or 95.9%; 1 R: if % is omitted 7bii HISP A MP1. less + carbon dioxide / CO2; MP2. less CO2 + less greenhouse gas / slow greenhouse effect / global warming; MP3. reduced/ slow down climate change effect; MP4. increase + biodiversity AW; MP5. decrease in methane from animals; MP6. make ref to / compare data in table 6.1; max 4 Total: 8 Ig: response which does not explain benefits

S4E BIOLOGY USS Prelim Exam 2023 Mark Scheme P1 P2 Page 5 of 7 Question C3R Answer Part Marks Marker’s Annotations 8ai HISP A MP1. both axes labelled + units + linear scales; time/min on x-axis + temperature/oC on y-axis MP2. good use of grid (3/4 space used, lines occupy at least 5 grid sq) y-axis 35–70 °C; MP3. correct plots for all line graphs; MP4. lines of best fit drawn; MP5. lines identified by label or key; 1m each 5 R: use of t to represent time or temperature R: [MP4] extrapolation beyond last plot A: plots joined by clear, straight lines for MP4. 8aii HISP A MP1. temperature decreases/ falls/ in all three; MP2. most/ fastest in A; MP3. least in B/ stays about the same; MP4. intermediate in C / AW; MP5. temperature changes calculated for each tube e.g. A: 34°C and B: 3°C and C: 10°C; max 3 8aiii HISP A MP1. Improvement: repeat / replicate; Explanation: increase reliability / identify error / calculate mean / average; MP2. Improvement: use hotter water at start; Explanation: greater difference in temperature of water and room / heat loss more pronounced; MP3. Improvement: same volume of water in all tubes at start; Explanation: same amount of heat available to be lost / AW; max 2 Ig. wrapping / insulating thermometers are not mentioned as the method of measuring temperature so Ig. refs.