than the concentration inside Cell A.\n\nExplain how the sub-cellular structures in Cell A help to transport dissolved sugars into the phloem sieve tube element.","markscheme":"- Identifies Structure B as **mitochondria** B1\n- States that mitochondria carry out **aerobic respiration** to release **energy** (or ATP) M1\n- Explains that this energy is required for **active transport** M1\n- Explains that active transport moves dissolved sugars **against/up their concentration gradient** (from Cell A into the phloem sieve tube element) A1","marks":4,"order":2,"markingRubric":null,"explanation":{"methods":[{"id":"active_transport","label":"Link structure to transport","steps":[{"type":"text","order":0,"title":"Compare the concentrations","content":"The dissolved sugars move from Cell A, where their concentration is lower, into the phloem sieve tube element, where their concentration is higher. This is movement against the concentration gradient. State this direction to earn the A1 mark.","highlights":[{"text":"The concentration of dissolved sugars inside the phloem sieve tube element is higher than the concentration inside Cell A.","location":"specification"}]},{"type":"text","order":1,"title":"Identify Structure B","content":"Structure B is a **mitochondrion**; the plural is **mitochondria**. Its bean-like outline and folded inner membrane identify it.\n\nWriting **mitochondria** earns **B1**.","highlights":[{"text":"Structure B","location":"specification"}]},{"type":"text","order":2,"title":"State mitochondria's role","content":"Mitochondria are the site of **aerobic respiration**. Aerobic respiration releases energy (in ATP) for cell processes.\n\nState both respiration and released energy to earn this **M1**.","highlights":[{"text":"sub-cellular structures in Cell A","location":"specification"}]},{"type":"text","order":3,"title":"Link energy to transport","content":"This movement requires active transport, using the energy released by aerobic respiration in the mitochondria. Linking energy released by respiration to active transport earns the M1 mark.","highlights":[{"text":"into the phloem sieve tube element","location":"specification"}]}]}],"generatedAt":"2026-07-22T12:10:58.142Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]},{"id":"29ead658-4e9b-413c-98db-95b7b97a27a1","label":"d","content":"During differentiation, unspecialized cells undergo structural changes to become functional sieve tube elements. Describe one structural change that occurs during this process.","markscheme":"- Describes one structural change: loss of nucleus, loss or reduction of cytoplasm, loss of organelles (such as ribosomes or mitochondria), or development of perforated end walls (sieve plates) B1","marks":1,"order":3,"markingRubric":null,"explanation":{"methods":[{"id":"sieve_tube_differentiation","label":"Identify one structural change","steps":[{"type":"text","order":0,"title":"Focus on structure","content":"The question asks for **one structural change** as an unspecialised cell becomes a functional sieve tube element. Give a physical change to the cell itself, rather than explaining its job.\n\nA precise valid answer is: **The cell loses its nucleus during differentiation.** This earns the B1 mark.","highlights":[{"text":"Describe one structural change that occurs during this process.","location":"specification"}]}]}],"generatedAt":"2026-07-22T12:11:29.949Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"8f4d4a86-d1a8-4776-941b-1b129dfd4388","revisionId":"4385a009-89c5-482a-be57-8bc25d188a45","questionNumber":null,"questionType":"LA","specification":"A student is growing tomato plants (*Solanum lycopersicum*) hydroponically. In one of the nutrient solutions, the student accidentally omits magnesium ions ($\\text{Mg}^{2+}$).","difficulty":3,"difficultyBand":"medium","totalMarks":2,"sourceTitle":null,"calculatorUse":null,"pa

2.3 Plant tissues, organs and systems

Question 10

2.3 Plant tissues, organs and systems Questions

2.3 Plant tissues, organs and systems

Question 10

2.3 Plant tissues, organs and systems Questions