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Multiple Choice
Which of the following statements best describes a receptor potential?
A
It is the resting membrane potential maintained by all cells in the absence of stimulation.
B
It is the potential difference generated by the sodium-potassium pump during active transport.
C
It is a graded change in membrane potential that occurs in response to a stimulus at a sensory receptor.
D
It is an all-or-nothing electrical signal that travels along the axon of a neuron.
Verified step by step guidance
1
Step 1: Begin by understanding the concept of a receptor potential. A receptor potential is a graded change in the membrane potential of a sensory receptor cell in response to a stimulus. It is not an all-or-nothing signal like an action potential, but rather varies in magnitude depending on the strength of the stimulus.
Step 2: Compare the receptor potential to the resting membrane potential. The resting membrane potential is the baseline electrical charge across the membrane of a cell when it is not being stimulated. This is different from a receptor potential, which occurs specifically in response to a stimulus.
Step 3: Examine the role of the sodium-potassium pump. The sodium-potassium pump actively transports sodium (Na⁺) out of the cell and potassium (K⁺) into the cell, maintaining the resting membrane potential. However, this is not directly related to receptor potentials, which are caused by ion channel activity in response to a stimulus.
Step 4: Distinguish receptor potentials from action potentials. Action potentials are all-or-nothing electrical signals that propagate along the axon of a neuron. In contrast, receptor potentials are localized, graded changes in membrane potential that occur at sensory receptor cells.
Step 5: Conclude that the correct description of a receptor potential is: 'It is a graded change in membrane potential that occurs in response to a stimulus at a sensory receptor.' This definition highlights the key characteristics of receptor potentials and distinguishes them from other types of electrical signals in cells.