Explain threshold-dependent sodium entry followed by potassium movement during depolarization and repolarization.
Tę umiejętność sprawdza 12 zadań wzorowanych na arkuszach IB z lat 2022–2026.
The trace shows an action potential in an axon. What is the state of the voltage-gated channels at X? Treat an inactivated sodium channel as closed to ion flow. A. Potassium channels conduct; sodium channels do not conduct B. Sodium channels conduct; potassium…
Explain how this channel contributes to an action potential.
A eukaryotic cell depends on membranes to organize reactions, exchange materials and respond to signals. (a) Discuss the benefits of membrane-bound compartments. (b) Describe mechanisms that move materials across the cell boundary. (c) Explain how axon…
The trace shows a neuronal action potential. At which labelled region do voltage-gated sodium channels open during this action potential? A. P B. R C. Q D. S
Which ion movement explains the falling portion of the action potential marked Y? A. Potassium leaves through open potassium channels B. Potassium enters through the channels to make the inside more positive C. A sodium pump switches on only when threshold is…
An experimental compound acts on potassium channels. Which effect explains the difference between the traces? A. Reduced outward potassium movement prolongs repolarization and the action potential B. Reduced inward potassium movement immediately speeds…
Which sequence describes the main membrane events in a neuronal action potential? A. Sodium channels close → sodium enters → repolarization → potassium is synthesized B. ATP leaves the axon → the nucleus depolarizes → sodium channels are removed C. Sodium…
Four stimuli of increasing strength are applied at t1–t4. Which inference is supported by the trace? A. The fourth response rises by only 32 mV from rest B. The threshold is approximately −32 mV C. Only the fourth stimulus changes membrane potential at all D.…
Four stimuli of increasing strength are applied at t1–t4. Which inference is supported by the trace? A. The fourth response rises by only 32 mV from rest B. The threshold is approximately −32 mV C. Only the fourth stimulus changes membrane potential at all D.…
State what occurs when the threshold is reached.
Describe ion movement during the rising and falling parts of interval t.
Cell specialization depends on coordinated cellular processes. (a) Outline processes occurring during interphase. (b) Describe how an action potential propagates along an axon. (c) Explain how cells in blood produce a specific immune response.
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