Ion Channels Overview

<p>Voltage-gated (D)</p> Signup and view all the answers

<p>They open in response to the binding of signaling molecules (A)</p> Signup and view all the answers

<p>The channel is open but blocked by a ball domain (D)</p> Signup and view all the answers

<p>Charged particles like ions (D)</p> Signup and view all the answers

<p>To transfer small molecules between cells (B)</p> Signup and view all the answers

<p>Membrane potential (A)</p> Signup and view all the answers

<p>Voltage-gated sodium channels (A)</p> Signup and view all the answers

<p>Both consist of large α subunits with homologous repeat domains (B)</p> Signup and view all the answers

<p>Repolarization of the cell membrane (C)</p> Signup and view all the answers

<p>Hyperpolarization-activated cyclic nucleotide-gated channels (D)</p> Signup and view all the answers

<p>They open in a strongly pH-sensitive manner (C)</p> Signup and view all the answers

<p>They modulate heart rate as peacemaking channels (C)</p> Signup and view all the answers

<p>They primarily function during depolarization (D)</p> Signup and view all the answers

<p>Facilitate acid extrusion from cells (B)</p> Signup and view all the answers

<p>NADPH oxidase (C)</p> Signup and view all the answers

<p>Ligand-gated channels (D)</p> Signup and view all the answers

<p>Nicotine receptor (B)</p> Signup and view all the answers

<p>They allow potassium to flow into the cell (B)</p> Signup and view all the answers

<p>Second messengers from inside the cell (D)</p> Signup and view all the answers

<p>It regulates channel activation (D)</p> Signup and view all the answers

<p>Nutrient absorption in the gut (A)</p> Signup and view all the answers

<p>To facilitate the diffusion of ions across the membrane (C)</p> Signup and view all the answers

<p>Passive transport (D)</p> Signup and view all the answers

<p>Ion channels form hydrophilic pores across membranes, unlike carrier proteins (B)</p> Signup and view all the answers

<p>It regulates the activity of the ion channels (B)</p> Signup and view all the answers

<p>SO4^2- (B)</p> Signup and view all the answers

<p>Ion channels allow a higher rate of ion transport, over 1 million ions per second (B)</p> Signup and view all the answers

<p>They mediate electrical signaling. (D)</p> Signup and view all the answers

<p>Ion selectivity (B)</p> Signup and view all the answers

<p>The diameter of the selectivity filter (D)</p> Signup and view all the answers

<p>The selective and narrow pores (C)</p> Signup and view all the answers

<p>Brief opening in response to stimuli (C)</p> Signup and view all the answers

<p>They connect the cytoplasm of adjacent cells through channel proteins (A)</p> Signup and view all the answers

<p>They modulate ion channel conductance. (D)</p> Signup and view all the answers

<p>Muscle contraction (A)</p> Signup and view all the answers

<p>Hydrophobic barrier created by phospholipid bilayers (B)</p> Signup and view all the answers

<p>They play a critical role in various biological functions. (C)</p> Signup and view all the answers

<p>Intracellular Ca2+ (D)</p> Signup and view all the answers

<p>Cyclic nucleotide-gated channels (D)</p> Signup and view all the answers

<p>Two-pore-domain potassium channels (C)</p> Signup and view all the answers

<p>Regulatory RNA molecules (C)</p> Signup and view all the answers

<p>Primarily permeable to monovalent cations (D)</p> Signup and view all the answers

<p>Light-gated channels (A)</p> Signup and view all the answers

<p>They contain two KV-style six-transmembrane domains. (D)</p> Signup and view all the answers

<p>Transient receptor potential channels (D)</p> Signup and view all the answers

Ion channels are membrane proteins that create pathways for ions to cross the cell membrane.

Cell membranes are made of a phospholipid bilayer, which creates a barrier to charged molecules like ions.

Ion channels allow ions to move across the membrane much faster than carrier proteins.

Ion channels are highly selective, meaning they only allow certain types of ions to pass through.

Ion channels play a crucial role in nerve impulse transmission, muscle contraction, and hormone secretion.

The activity of ion channels can be regulated by phosphorylation, a process that adds a phosphate group to a protein.

Gap junctions are formed by channel proteins that connect the cytoplasm of two adjacent cells.

Ion channels are crucial for maintaining the electrochemical gradient across cell membranes, which is vital for many cellular processes.

The mechanism by which ion channels open and close is called gating.

Voltage-gated ion channels open or close in response to a change in the electrical potential across the cell membrane.

Ligand-gated ion channels open or close in response to the binding of a specific signaling molecule.

Ion channels are highly selective, only allowing certain types of ions to pass through.

Ion channels fluctuate between open and closed states, allowing them to control the flow of ions across the membrane.

Ion channels play a critical role in nerve impulse conduction, muscle contraction, and many other cellular processes.

Ion channels are affected by a variety of factors, including changes in voltage, the binding of ligands, and mechanical stress.

Ion channels that open or close in response to changes in the membrane potential.

Responsible for action potential generation and propagation. Their structure consists of four repeat domains (I-IV). They also interact with auxiliary beta subunits.

Play a vital role in linking muscle excitation to contraction and neuronal excitation to neurotransmitter release. Structurally similar to sodium channels.

A small family of channels related to two-pore channels and distantly related to TRP channels. They are involved in sperm motility.

Primarily known for repolarizing the cell membrane after action potentials. They have six transmembrane segments, assembling as tetramers to form a functional channel.

Open in response to hyperpolarization rather than depolarization. They are sensitive to cAMP & cGMP, altering their voltage sensitivity. Permeable to K+ and Na+.

Open with depolarization but are strongly pH-sensitive. They play a role in regulating pH balance and cellular processes.

Ion channels that open or close in response to mechanical stimulation, such as stretching or pressure.

This type of potassium channel is opened by the presence of calcium ions (Ca2+) inside the cell.

This type of channel leaks ions constantly, even without a specific trigger.

These channels respond to light, opening when light strikes them. They are found in sensory photoreceptors.

These channels open in response to physical forces like stretch, pressure, or displacement.

These channels open when cyclic AMP (cAMP) or cyclic GMP (cGMP) bind to them.

This channel family is activated by a change in voltage across the cell membrane.

These channels are permeable to many different ions, making them relatively non-specific.

This family of channels is diverse in its activation methods, including voltage, calcium, pH, and mechanical stretch.

Proton channels that open only when the electrochemical gradient is outward, allowing protons to leave cells.

These channels are important for acid extrusion from cells, balancing the movement of electrons across the membrane.

Ion channels that open in response to specific ligand molecules binding to their extracellular domain.

Examples of ligand-gated channels: nicotinic acetylcholine receptor, ionotropic glutamate-gated receptors, and GABA receptor.

Ion channels that respond to intracellular second messengers rather than extracellular ligands.

Some potassium channels that allow potassium to flow into the cell in an inwardly rectifying manner.

These channels are influenced by intracellular molecules like ATP, PIP2, and G-protein βγ subunits.

Inward-rectifier potassium channels play a role in heart pacemaker activity, insulin release, and potassium uptake in glial cells.

The process of moving specific ions across a cell membrane without requiring energy is called passive transport. Ion channels facilitate this movement by allowing ions to flow from areas of high concentration to areas of low concentration (downhill).

Ion channels are highly selective, allowing only certain ions to pass through their pore. This selectivity is crucial for maintaining cell function and proper signaling.

Ion channels are not always open. Instead, they have gates that open and close in response to specific stimuli. This allows cells to control the flow of ions and regulate their electrical activity.

Voltage-activated channels open and close in response to changes in membrane potential. This is crucial for generating and propagating nerve impulses.

Transmitter-activated channels are opened by specific neurotransmitters released from presynaptic neurons. This allows for communication between neurons at synapses.

Ion channels play a crucial role in muscle contraction. They help regulate the flow of ions that trigger muscle fiber activation.

Ion channels are important targets for drug development because they play a role in various physiological processes. By modulating their activity, drugs can treat a variety of diseases.