Question

When comparing action potentials to graded potentials, an/two important distinguishing characteristic/s is/are

A. graded potentials can undergo summation.

B. action potentials can undergo summation.

C. that the rate of action potentials is limited by the refractory period.

D. graded potentials can undergo summation and the rate of action potentials is limited by the refractory period.

E. action potentials can undergo summation and the rate of action potentials is limited by the refractory period.

Answer 1

Graded potentials can summate and lead to an action potential reaching the threshold, while action potentials cannot summate due to the refractory period, which limits the rate at which they can occur.

Step-by-step explanation:

When comparing action potentials to graded potentials, two important distinguishing characteristics are that graded potentials can undergo summation and the rate of action potentials is limited by the refractory period. Graded potentials are changes in the membrane potential that can add together to reach the threshold necessary to initiate an action potential. Summation can either be spatial, involving multiple locations on a neuron, or temporal, involving multiple occurrences separated in time.

Action potentials differ in that they do not summate due to the refractory period, which is the time after the initiation of an action potential when another one cannot be generated. This period has two phases: the absolute and relative refractory periods. During the absolute refractory period, action potentials cannot be initiated regardless of the stimulus strength due to the inactivation of Na+ channels. The relative refractory period may allow an action potential to be initiated, but only by a stronger stimulus.