Relate channel structure and opening to the passive movement of particular ions across membranes.
Tę umiejętność sprawdza 11 zadań wzorowanych na arkuszach IB z lat 2022–2026.
At constant temperature, I represents simple diffusion and II represents channel-mediated diffusion. Which interpretation of the labelled positions is valid? A. At W, the particles have lost most of their thermal energy B. At X, the finite number of channels…
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…
Compare and contrast simple diffusion and facilitated diffusion across a membrane.
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…
A membrane allows oxygen to pass directly through its lipid bilayer and a particular ion to pass through channels. Which distinction between these two passive processes is correct? A. Ion movement through a channel must be against its concentration gradient B.…
Which labelled regions in this membrane model are hydrophilic? A. I and II B. III and IV C. I and III D. II and IV
A cell uses both facilitated diffusion and active transport. What feature can these processes share? A. Direct passage of every solute through the lipid core B. An obligatory release of oxygen C. Movement through integral membrane transport proteins D. A…
A neutral solute crosses a membrane through a selective channel. There is initially more of it outside than inside; no other process moves or consumes it. Which description fits this facilitated diffusion? A. ATP must be hydrolysed for every molecule…
(a) Describe protein structure, distinguishing shared features from features that can vary. (b) Explain how proteins enable substances to move across cell membranes.
Nutrients move from the intestinal lumen into the circulation and then reach the liver. Explain adaptations of villus epithelial cells for absorption and what can happen to absorbed nutrients in the liver.
Membrane transport and kidney function contribute to water and solute balance. (a) Outline four different ways substances cross the plasma membrane, giving an example for each. (b) Explain how kidney regions contribute to water balance and excretion of…
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