Paper 2 style practice paper: Multiple choice (Extended) — mark scheme
QuizQuipPractice Series
QQ/IGCSE-BIO/P2S
IGCSE · Cambridge IGCSE Biology (Extended)
Mark scheme
Multiple choice (Extended)
Paper 2 style practice paper · Maximum mark: 40
Notes for markers
- Award one mark for each point marked [1], up to the marks shown for the part.
- Accept answers worded differently that show the same understanding.
- Units are required where the answer line shows one. ecf: allow an error carried forward.
Section A: Multiple-choice questions[40 marks]
| Question | Answer | |
|---|---|---|
| 1 | AExcretion removes metabolic waste (e.g. carbon dioxide, urea); egestion removes undigested food. | 1 |
| 2 | BFur and milk-feeding are the diagnostic mammal features within the vertebrates. | 1 |
| 3 | CCloser relatives share more base sequence similarity — DNA underpins modern classification (Supplement). | 1 |
| 4 | DBoth have cell walls; bacteria lack nuclei, chloroplasts and mitochondria. | 1 |
| 5 | AActual size = image size ÷ magnification = 8 ÷ 400 = 0.02 mm. | 1 |
| 6 | BWater moves by osmosis from higher to lower water potential — out of the cell into the concentrated solution. | 1 |
| 7 | CBiuret → purple for protein; iodine is starch, Benedict is reducing sugar, ethanol is fat. | 1 |
| 8 | DHeat above the optimum destroys active-site shape — denaturation. | 1 |
| 9 | ALeaves have no blood — the standard limiting factors are CO₂, light and temperature. | 1 |
| 10 | BPalisade cells sit at the top where light is strongest, packed with chloroplasts. | 1 |
| 11 | CVitamin C deficiency → scurvy; D deficiency → rickets; iron deficiency → anaemia. | 1 |
| 12 | DVilli give a huge surface area with a rich blood supply for absorption. | 1 |
| 13 | AXylem vessels carry water and ions upward; phloem carries sucrose both ways. | 1 |
| 14 | B6.0 ÷ 3.0 = 2.0 cm³ per minute. | 1 |
| 15 | CThe left ventricle drives the systemic loop at high pressure. | 1 |
| 16 | DThe insoluble fibrin mesh traps cells and dries into the scab (Supplement). | 1 |
| 17 | ADisease-causing organism — bacterium, virus, fungus or protoctist. | 1 |
| 18 | BLymphocytes make antibodies and memory cells that persist (Supplement). | 1 |
| 19 | CRespiration uses O₂ and releases CO₂ — 21%→16% O₂, 0.04%→4% CO₂. | 1 |
| 20 | DFermentation: glucose → alcohol + CO₂; the balanced form is C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ (Supplement). | 1 |
| 21 | AThe liver deaminates excess amino acids; the kidneys only excrete the urea. | 1 |
| 22 | BAll the glucose is reabsorbed — urine contains none (Supplement). | 1 |
| 23 | CFive boxes in order — receptor, sensory, relay, motor, effector. | 1 |
| 24 | DAntagonistic action: circular contracts, radial relaxes → pupil narrows (Supplement). | 1 |
| 25 | AInsulin → liver stores glucose as glycogen; glucagon reverses it (Supplement). | 1 |
| 26 | BUnequal elongation bends the shoot towards the light (Supplement). | 1 |
| 27 | CAnther → stigma, by insect, wind or other agent. | 1 |
| 28 | DAmniotic fluid inside the amniotic sac cushions the fetus. | 1 |
| 29 | AGenotypes 1:2:1; phenotypes 3 tall : 1 short. | 1 |
| 30 | BNo recessive offspring → the unknown could only supply T alleles (Supplement). | 1 |
| 31 | COne recessive X allele expresses in XY males; females need both Xs affected (Supplement). | 1 |
| 32 | DA smooth range between extremes — genes and environment together. | 1 |
| 33 | AMutation creates genetic change — the source of every new allele. | 1 |
| 34 | BDifferential reproduction is the engine of selection. | 1 |
| 35 | CProducers fix sunlight into chemical energy first. | 1 |
| 36 | DThe oxygen is consumed by decomposer respiration after the algal bloom (Supplement). | 1 |
| 37 | AMethane is a potent greenhouse gas alongside carbon dioxide. | 1 |
| 38 | BFermentation: glucose → ethanol + carbon dioxide. | 1 |
| 39 | CRestriction enzymes cut; DNA ligase seals (Supplement). | 1 |
| 40 | DGene flow to wild relatives is a recognised ecological risk (Supplement). | 1 |
— End of mark scheme —