Final answer:
Voltage-gated ion channels are the receptor proteins that change membrane voltage immediately upon activation, allowing for rapid initiation of action potentials.
Step-by-step explanation:
The receptor proteins that change membrane voltage immediately when activated are known as voltage-gated ion channels. These channels can quickly open or close in response to changes in the electrical potential across the cell membrane. When activated, these channels allow ions to pass through, leading to an immediate change in membrane voltage. However, they also inactivate shortly after opening, preventing further changes in voltage until they reset.
G-protein-linked receptors, on the other hand, do not directly change membrane voltage upon activation. Instead, they activate a G-protein, which then interacts with other proteins, such as ion channels or enzymes, to modulate cellular responses over a longer duration. These receptors have seven transmembrane domains and bind specific ligands to initiate their signaling pathways.
Therefore, it is the voltage-gated ion channels that are responsible for instantaneous changes in membrane voltage, crucial for processes such as the initiation of action potentials in neurons.
Voltage-gated ion channels change membrane voltage immediately when activated.
These ion channels open in response to changes in membrane voltage, allowing ions such as sodium (Na+) or potassium (K+) to cross the membrane and generate an electrical signal.
Examples of voltage-gated ion channels include the sodium channel and the potassium channel.