Strengths: good grasp of osmosis, fertilisation, organ locations/functions, respiration basics and synaptic transmission; IVF understood.
Weaker areas: biological molecules, limiting factors for photosynthesis, digestion & absorption, exercise responses, variation; vessel & breathing system structure; ECG function; % offspring in monohybrid crosses.
Exam advice: read graphs precisely (e.g. Q11) and the full question (e.g. Q2, Q38).
(a) Must state that carbon dioxide is required for photosynthesis, not just that CO? was removed by reagents. Difficult
(b) Iodine test: best answers linked starch formation to photosynthesis; many only named the test. Moderate
(c)(i) Read highest rate from graph correctly. Easy
(c)(ii) Calculated difference in rate fairly well. Moderate
(c)(iii) Lowest light intensity at max rate read less accurately. Moderate
(c)(iv) Explain why increasing light raises the graph: light supplies energy for photosynthesis. Many only said “rate rises”. Difficult
(d) Other raw material is water; “sunlight” is not a raw material. Easy
(e) Site of photosynthesis is the chloroplast; common errors: “chlorophyll” or “palisade mesophyll”. Moderate
(f)(i) % increase formula often not used or wrong S.F. Moderate
(f)(ii) Correct conclusion chosen by most. Easy
(a) Cloze passage completed well. Easy
(b)(i) Position of the blind spot poorly identified by many. Difficult
(b)(ii) Mixed recall of cornea vs iris; retina/optic nerve better known. Moderate
(b)(iii) Functions: iris controls light entry; lens focuses on retina. Many confused these. Difficult
(a) Herbivore and an animal acting as both secondary & tertiary consumer identified; quaternary/trophic-level items were harder. Moderate
(b)(i) Pyramids of numbers: many good, some inverted or mislabelled producer/top. Moderate
(b)(ii) Energy source: not just “the Sun directly” — explain transfer via producers. Moderate
(b)(iii) “Overharvesting” often misread; food-web links unclear. Difficult
(c)(i) “Insecticides kill insects” needs consequence (crop damage avoided / higher yield). Moderate
(c)(ii) Human impacts on birds: list distinct reasons (e.g., habitat loss, pollution, hunting), not variations of one. Moderate
(a)(i) Two distinct points required (change in plastic waste production rate & total mass); quote graph + units. Difficult
(a)(ii) 50% recognised by many. Easy
(a)(iii) “Sustainable resource” definition weak; re-use/recycle alone isn’t enough. Difficult
(a)(iv) Rising CO? ? global warming; give effects (e.g., sea-level rise, habitat loss). Ozone/acid-rain confusions common. Difficult
(b) Effects of plastic pollution in oceans: stronger answers detailed food-chain harm, entanglement, ingestion; weak answers said “dirty”. Moderate
(a)(i) Definition of a gene needed; paraphrases lost credit. Moderate
(a)(ii) Insulin lowers blood glucose; many wrote it “controls the concentration”. Moderate
(a)(iii) Other GMO uses (besides biofuels) rarely given (e.g., pest-resistant crops, pharmaceuticals). Difficult
(a)(iv) Advantages of using bacteria in genetic modification largely unknown/misunderstood. Difficult
(b) Bacterial vs plant cells: most scored one difference; common misconception that bacteria lack cell walls. Moderate
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