Questions and Answers
What is the primary function of ligand-gated ion channels?
What type of membrane receptors are ligand-gated ion channels?
Where are ligand-gated ion channels commonly found?
What is the term for the specific binding of a ligand to a receptor?
Signup and view all the answers
What is the shape of the ligand complementary to?
Signup and view all the answers
What is the function of the kink in the ion channel?
Signup and view all the answers
What is the term for transmembrane ion channels?
Signup and view all the answers
What is the environment inside the cell?
Signup and view all the answers
What happens to the closed channel when a ligand binds to the allosteric site?
Signup and view all the answers
What is the main purpose of membrane receptors?
Signup and view all the answers
What type of ion channels rely on the difference in membrane potential?
Signup and view all the answers
What is the result of ions moving through the open channel?
Signup and view all the answers
What is the term for the binding site of the ligand that is not on the channel itself?
Signup and view all the answers
What is the effect of multiple allosteric binding sites on a protein?
Signup and view all the answers
What is the characteristic of stretch-activated ion channels?
Signup and view all the answers
What is the significance of the ligand binding to the allosteric site?
Signup and view all the answers
What is the result of the conversion of an extracellular ligand signal to an intracellular electrical signal?
Signup and view all the answers
What is the characteristic of ligand-gated ion channels?
Signup and view all the answers
Study Notes
Ligand-Gated Ion Channels
- Ligand-gated ion channels are a type of major membrane receptors that open or close in response to the binding of a chemical messenger (ligand).
- There are three categories of major membrane receptors: ligand-gated ion channels, G protein-coupled receptors, and enzyme-linked receptors.
- Ligand-gated ion channels are commonly found in electrically excitable cells, such as neurons, due to their quick reaction to ligand binding.
Structure and Function
- Ligand-gated ion channels are transmembrane ion channels with a channel or hole through which ions can move in and out.
- The channel has a specific binding site for a ligand, which is complementary to the shape of the ligand.
- Only specific ligands can bind to specific channels, following the "lock and key" or "induced fit" principle.
- When a ligand binds, it causes the channel to open, allowing ions to move through the membrane.
Allosteric Binding
- The binding site of the ligand is not near the actual channel, but rather at an allosteric site.
- The binding of the ligand to the allosteric site causes a change in the protein conformation, which opens the channel.
- The allosteric binding site can be intracellular, but it is generally located on the extracellular side.
Ion Permeability and Electrical Signal
- When the channel opens, ions such as potassium, sodium, chlorine, or calcium can move through the membrane.
- This change in ion permeability causes a change in the electrical properties of the cell.
- The movement of ions in and out of the cell generates an intracellular electrical signal.
Key Distinctions
- Ligand-gated ion channels are not the same as voltage-gated ion channels, which rely on the difference in membrane potential.
- Ligand-gated ion channels are also distinct from stretch-activated ion channels, which depend on the deformation of the cell membrane.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Learn how ligand-gated ion channels enable quick reactions in the nervous system, including neurons and the brain. Understand the three categories of major membrane receptors.