Graded potentials are:
arise when ion movement causes a minor change in the resting membrane potential.
usually propagate down the length of an axon.
occur when voltage-gated channels open.
are most often observed in axons.
are usually associated with ion movement through leakage channels.
(choose the correct answer from these choices)
The correct answer is: "arise when ion movement causes a minor change in the resting membrane potential."
The correct answer is: arise when ion movement causes a minor change in the resting membrane potential.
To arrive at this answer, we can analyze each choice and determine if it accurately describes graded potentials:
1. Graded potentials arise when ion movement causes a minor change in the resting membrane potential. This statement accurately describes graded potentials.
2. Graded potentials usually propagate down the length of an axon. This statement is incorrect. Graded potentials are generally localized and do not spread as action potentials do.
3. Graded potentials occur when voltage-gated channels open. This statement is incorrect. Graded potentials can arise from different types of ion channels, including ligand-gated channels and leakage channels, not exclusively voltage-gated channels.
4. Graded potentials are most often observed in axons. This statement is incorrect. Graded potentials can occur in various types of excitable cells such as neurons, muscle cells, and sensory cells, not exclusively in axons.
5. Graded potentials are usually associated with ion movement through leakage channels. This statement is incorrect. Graded potentials can result from ion movement through multiple types of channels, including leakage channels but not exclusively.
Hence, only the first statement accurately describes graded potentials.