Explain how ATP-driven exchange of sodium and potassium contributes to ion gradients and membrane potential.
Tę umiejętność sprawdzają 4 zadania wzorowane na arkuszach IB z lat 2023–2025.
A cell maintains the ion concentrations shown. Which mechanism can sustain these opposing gradients? Ion | Cytosol / mmol L⁻¹ | External fluid / mmol L⁻¹ Potassium | 142 | 4.5 Sodium | 12 | 138 A. Passive movement of both ions through permanently open channels…
Specific molecular interactions occur in several biological systems. (a) Explain how a vaccine can produce specific immunity against a viral infection. (b) Outline how membrane proteins control movement of particular ions at different stages of a nerve…
What conclusion about sodium transport follows from this membrane model? A. Sodium leaves through the ATP-powered transporter and can return through a channel B. Sodium leaves by simple diffusion through lipid and returns by protein synthesis C. Every sodium…
In establishing the ionic gradients associated with a neuronal resting potential, what is the action of the sodium–potassium pump? A. It exchanges sodium outwards for potassium inwards B. It moves both ions only into the neuron C. It converts sodium ions into…
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