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Chapter 5: Movement of Ions Across Biological Membranes: Ion Transporters & Channels
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Why is the concentration of chloride in virtually all neurons lower inside than outside?
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A. All neurons have chloride transporters that reduce the intracellular concentration.
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B. The hyperpolarizing phase of action potentials pushes chloride outside the cell.
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C. The negative potential inside neurons causes exiting of chloride ions through leakage channels.
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D. Chloride accompanies the exit of sodium in the sodium/potassium active transporter.
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E. None of the above are correct.
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C. The negative potential inside neurons causes exiting of chloride ions through leakage channels.
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What active ion transporter in neurons is necessary for the ionic concentration differences underlying the action potential?
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C. Na+/Ca2+ exchange pump
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A. The Na+/K+ ATP pump is necessary for the ionic concentration differences underlying the action potential.
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What other molecules beside ions are transported across neural membranes by active pumps?
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B. Amino acids and neurotransmitters
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D. Molecules with phenyl rings
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B. Amino acids and neurotransmitters are transported across neural membranes by active pumps.
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What voltage-gated ion channel causes the relative refractory period?
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D. The K+ ion channel causes the relative refractory period.
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What does the term ligand-gated mean?
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C. Opened by concentration differences
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D. Opened by liganic ions
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