Question

Determine whether each phrase describes ligand-gated ion channels, voltage-gated ion channels, or both.

1) Ligand-gated ion channels
2) Voltage-gated ion channels
3) Both

Answer 1

Ligand-gated ion channels open in response to neurotransmitter binding, while voltage-gated ion channels open due to changes in membrane voltage. Both are critical for neurotransmission. So, the correct answer is option 3.

Step-by-step explanation:

The student's question concerns different types of ion channels found in cell membranes and requires the identification of descriptions that pertain to ligand-gated ion channels, voltage-gated ion channels, or both. Ligand-gated ion channels are those that open in response to the binding of a signaling molecule, or ligand, such as a neurotransmitter, to a specific site on the channel.

This action allows ions to pass through the membrane, altering the cell's charge. On the other hand, voltage-gated ion channels are prompted to open by changes in the electrical charge, or voltage, across the cell's membrane, an essential feature in the transmission of electrical impulses in neurons and muscle cells.

Thus, the phrases presented can be categorized as follows:

1. Ligand-gated ion channels open when a neurotransmitter like acetylcholine binds to the channel, permitting cations such as sodium, calcium, and potassium through.
2. Voltage-gated ion channels open due to changes in voltage across the membrane, which is pivotal in the action potential generation in neurons and muscle cells.
3. Both types of channels are essential for neurotransmission, as they contribute to the changes in membrane potential that facilitate neuronal signaling and muscle contractions.