Zadanie 8, Paper 2, listopad 2025, TZ3, Biologia IB HL

(a) Maximum 7:

Sugars such as glucose or sucrose are water-soluble OR can be transported in aqueous fluids. ✔

Glucose is a respiratory substrate OR its oxidation releases energy. ✔

Condensation joins sugar monomers into long polymers. ✔

Starch or glycogen consists of glucose units (alpha-glucose). ✔

Starch contains amylose and amylopectin OR amylose is unbranched OR amylopectin is branched OR glycogen is highly branched. ✔

Starch or glycogen can be hydrolysed to release glucose rapidly when needed. ✔

Starch and glycogen store chemical energy. ✔

Coiling and packing allow many glucose units to occupy a small volume. ✔

Insoluble polymers exert little osmotic effect compared with free glucose OR storing equivalent free glucose would cause osmotic problems. ✔

Cellulose is a glucose polymer (beta-glucose). ✔

Successive cellulose glucose monomers alternate in orientation. ✔

Cellulose chains are crosslinked into bundles or microfibrils (through hydrogen bonding). ✔

Cellulose supports plant cell walls. ✔

Cellulose is insoluble OR has high tensile strength OR helps walls resist osmotic bursting. ✔

(b) Maximum 5:

ATP supports cell or chromosome movement, such as phagocyte migration or chromosome separation in anaphase. ✔

ATP drives ciliary or eukaryotic flagellar beating. ✔

ATP supports endocytosis or exocytosis. ✔

ATP allows myosin to detach from actin OR powers re-cocking of myosin heads. ✔

ATP drives active transport, such as the sodium–potassium pump. ✔

ATP supports anabolic reactions or macromolecule synthesis, for example protein synthesis. ✔

ATP turnover can generate heat that helps maintain body temperature or suitable enzyme conditions. ✔

ATP phosphorylates substrates during glycolysis. ✔

ATP supports substrate phosphorylation in the Calvin cycle, including GP processing or RuBP regeneration. ✔

(c) Maximum 3:

Respiratory carriers occur in cytosol or mitochondria, whereas photosynthetic carriers function in chloroplasts. ✔

Respiration primarily uses NADH; photosynthesis uses NADPH. ✔

Respiratory NADH is produced during glycolysis, the link reaction or Krebs cycle; photosynthetic NADPH is produced in light-dependent electron transfer. ✔

Respiratory NADH supplies oxidative phosphorylation; photosynthetic NADPH supplies reduction in the Calvin cycle. ✔

Construction:1 mark for clear, concise organization of the complete response, without substantial repetition or irrelevant material.

Award distinct points up to the individual part caps 7,5,3; maximum15 content marks plus1 independent construction mark, total16. In(b), cell/chromosome movement and active transport require a suitable example; a generic anabolic process or synthesis example suffices for its point. In(c), NAD⁺/NADP⁺ names are accepted for identifying the carrier systems; accept photosynthetic PSI/PSII/electron transport/chemiosmosis for the light-dependent production context and respiratory electron transport/chemiosmosis for oxidative phosphorylation; named Calvin-cycle reduction stages are acceptable.