Studies on the squid giant axon were instrumental to our current understanding of how action potentials are generated. You decide to do some experiments on the squid giant axon yourself.
A. You remove the cytoplasm in an axon and replace it with an artificial cytoplasm that contains twice the normal concentration of K+ by adding KOAc, where OAcâ is an anion to which the membrane is impermeable. In this way, you double the internal concentration of K+ while maintaining the bulk electrical balance of the cytoplasmic solution. Will this make the resting potential of the membrane more or less negative?
B. You add NaCl to the extracellular fluid and effectively double the amount of extracellular Na+ ions. How does this affect the action potential?
C. You replace half of the NaCl in the extracellular fluid with choline chloride. (Choline is a monovalent cation much larger than Na+. Note that the presence of choline will not impede the flow of Na+ through its channels.) How will this affect the action potential?
Studies on the squid giant axon were instrumental to our current understanding of how action potentials are generated. You decide to do some experiments on the squid giant axon yourself.
A. You remove the cytoplasm in an axon and replace it with an artificial cytoplasm that contains twice the normal concentration of K+ by adding KOAc, where OAcâ is an anion to which the membrane is impermeable. In this way, you double the internal concentration of K+ while maintaining the bulk electrical balance of the cytoplasmic solution. Will this make the resting potential of the membrane more or less negative?
B. You add NaCl to the extracellular fluid and effectively double the amount of extracellular Na+ ions. How does this affect the action potential?
C. You replace half of the NaCl in the extracellular fluid with choline chloride. (Choline is a monovalent cation much larger than Na+. Note that the presence of choline will not impede the flow of Na+ through its channels.) How will this affect the action potential?
