Actin filaments are incapable of lasting the entire lifetime
     Actin filaments are incapable of lasting the entire lifetime of the cell.  True  False  Which channel needs to be in the open state during the rising phase of an action potential?  Voltage-gated Na^+ channels  Voltage-gated K^+ channels  NaK pumps  Delayed rectifier K^+ channels  The action potential does not reverse direction on its own because  The voltage-gated K^+ channels are in their open state  The voltage-gated Na^+ channels cannot transition directly from inactive to open states.  The voltage-gated Na^+ channels are in their inactivated states.  The delayed rectifier K^+ channels cannot transition directly from inactive to open states.  If a neuron receives an excitatory input from another neuron, it will always fire an action potential.  True  False  The following is an example of an excitatory neurotransmitter.  Valine  GABA  Glycine  Acetylcholine 
  
  Solution
5. (a) True
Actin cytoskeleton is dynamic, it keeps rearranging and reorganizing according to celllular movements. Half life of actin filaments is shorter than the life time of a cell.
6.(a) Voltage gated sodium channels
As the stimulus crosses theshold potential, the Voltage gated sodium channels open and cause further depolarization of neuron.

