Which statement accurately describes ligand-gated ion channels?

Which statement accurately describes ligand-gated ion channels?

• A. They open in response to voltage changes
• B. They open when a neurotransmitter binds
• C. They are always open
• D. They transport molecules against their concentration gradient

Answer: (B)

Ligand-gated ion channels are membrane proteins that open in response to the binding of a specific molecule, known as a ligand, typically a neurotransmitter. When the neurotransmitter binds to the receptor site on the ion channel, it induces a conformational change in the protein that results in the opening of the channel. This allows specific ions (such as sodium, potassium, calcium, or chloride) to pass through the membrane, leading to changes in the membrane potential of the cell and facilitating signal transduction. This mechanism is crucial for synaptic transmission in neurons, as the binding of neurotransmitters can lead to rapid changes in intracellular ion concentrations, which are essential for processes such as muscle contraction, action potential generation, and various signaling pathways in the nervous system. In contrast, other types of ion channels, such as voltage-gated ion channels, respond to changes in membrane potential, and transporters are responsible for moving substances against their concentration gradients, which ligand-gated channels do not do.

Ligand-gated ion channels are membrane proteins that open in response to the binding of a specific molecule, known as a ligand, typically a neurotransmitter. When the neurotransmitter binds to the receptor site on the ion channel, it induces a conformational change in the protein that results in the opening of the channel. This allows specific ions (such as sodium, potassium, calcium, or chloride) to pass through the membrane, leading to changes in the membrane potential of the cell and facilitating signal transduction.

This mechanism is crucial for synaptic transmission in neurons, as the binding of neurotransmitters can lead to rapid changes in intracellular ion concentrations, which are essential for processes such as muscle contraction, action potential generation, and various signaling pathways in the nervous system. In contrast, other types of ion channels, such as voltage-gated ion channels, respond to changes in membrane potential, and transporters are responsible for moving substances against their concentration gradients, which ligand-gated channels do not do.