Zadanie 6, Paper 2, listopad 2024, TZ1, Biologia IB SL
Wzorowane na: Biology SL Paper 2, November 2024, TZ1, pytanie 6. Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
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Zadanie
Polecenie
A cell in a freshwater organism is bounded by a phospholipid membrane.
(a) Outline how phospholipid properties determine the membrane’s structure.
(b) Describe the movement of substances through the membrane by facilitated diffusion.
(c) Explain how electrical nerve impulses are transmitted along a neuron.
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Pokaż rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
(a) Phospholipids organize as a bilayer. ✔
Each has a phosphate-containing head and two fatty-acid tails. ✔
The heads are polar and hydrophilic. ✔
The tails are non-polar and hydrophobic. ✔
Tails occupy the water-excluding interior. ✔
Heads interact with water on both surfaces. ✔
(b) Particles move down their concentration gradient. ✔
The membrane core is hydrophobic. ✔
This route allows ions or other hydrophilic particles to cross. ✔
Transport uses membrane proteins. ✔
The proteins span the bilayer. ✔
Channels provide a hydrophilic passage. ✔
The process is passive and needs no direct ATP input. ✔
(c) Transmission involves movement of ions. ✔
Sodium-ion concentration is higher outside the neuron. ✔
The resting interior is negative relative to the exterior. ✔
Potassium-ion concentration is higher inside the neuron. ✔
ATP-dependent sodium–potassium pumping maintains these concentration differences. ✔
A nerve impulse consists of an action potential. ✔
The action potential is propagated to successive adjacent regions along the nerve fibre. ✔
Quality of communication: the whole response is clear, concise and organized, with little repetition or irrelevant material. ✔
Schemat punktowania
Part (a): any 4, maximum 4. Part (b): any 4, maximum 4. Part (c): seven distinct SL points, maximum 7; detailed channel kinetics, threshold, repolarization and saltatory conduction are not required. Award 1 independent communication mark. Maximum 16.
Umiejętności w zadaniu
- Action potentials as travelling nerve signalsĆwicz podobne
- The membrane's hydrophobic barrierĆwicz podobne
- Selective diffusion through protein channelsĆwicz podobne
- Ion gradients and the resting membrane voltageĆwicz podobne
- The lipid framework of membranesĆwicz podobne
- Protein positions within membranesĆwicz podobne