Chapter 5: Movement of Ions Across Biological Membranes: Ion Transporters & Channels

Chapter 5: Movement of Ions Across Biological Membranes: Ion Transporters & Channels

Why is the concentration of chloride in virtually all neurons lower inside than outside?

A. All neurons have chloride transporters that reduce the intracellular concentration.

B. The hyperpolarizing phase of action potentials pushes chloride outside the cell.

C. The negative potential inside neurons causes exiting of chloride ions through leakage channels.

D. Chloride accompanies the exit of sodium in the sodium/potassium active transporter.

E. None of the above are correct.

C. The negative potential inside neurons causes exiting of chloride ions through leakage channels.

What active ion transporter in neurons is necessary for the ionic concentration differences underlying the action potential?

A. Na⁺/K⁺ ATP pump

B. Ca²⁺ pump

C. Na⁺/Ca²⁺ exchange pump

D. Cl^– transporter pump

E. Na⁺/Cl^– ATP pump

A. The Na⁺/K⁺ ATP pump is necessary for the ionic concentration differences underlying the action potential.

What other molecules beside ions are transported across neural membranes by active pumps?

A. Glucose and dextrose

B. Amino acids and neurotransmitters

C. RNA

D. Molecules with phenyl rings

E. Enzymes

B. Amino acids and neurotransmitters are transported across neural membranes by active pumps.

What voltage-gated ion channel causes the relative refractory period?

A. Na⁺

B. Cl^–

C. Ca²⁺

D. K⁺

E. Mg²⁺

D. The K⁺ ion channel causes the relative refractory period.

What does the term ligand-gated mean?

A. Opened by stretch

B. Open only transiently

C. Opened by concentration differences

D. Opened by liganic ions

E....