What does the cell membrane allow to pass through it?
The most important property of the cell membrane is its selective permeability: some substances can pass through it freely, but others cannot. Small and nonpolar (hydrophobic) molecules can freely pass through the membrane, but charged ions and large molecules such as proteins and sugars are barred passage.
A receptor detects a signal molecule and carries out an action in response. A ligand is a molecule that acts as a signal when it binds to a receptor. A ligand that can cross the cell membrane can bind to an intracellular receptor. The cell membrane allows some, but not all, molecules to cross.
- In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electron pairs.
- The insulin receptor is a member of the ligand-activated receptor and tyrosine kinase family of transmembrane signaling proteins that collectively are fundamentally important regulators of cell differentiation, growth, and metabolism.
- While active transport requires energy and work, passive transport does not. There are several different types of this easy movement of molecules. It could be as simple as molecules moving freely such as osmosis or diffusion.
Receptor Proteins Exhibit Ligand-Binding and Effector Specificity. As noted earlier, the cellular response to a particular extracellular signaling molecule depends on its binding to a specific receptor protein located on the surface of a target cell or in its nucleus or cytosol.
- Hormone receptor. A hormone receptor is a receptor molecule that binds to a specific hormone. Hormone receptors are a wide family of proteins made up of receptors for thyroid and steroid hormones, retinoids and Vitamin D, and a variety of other receptors for various ligands, such as fatty acids and prostaglandins.
- Ligand. Molecule that specifically bonds to a larger molecule. Ligand binding causes a receptor protein to undergo a change in shape, which sometimes directly activates the receptor which allows it to interact with other cells. The signaling molecule behaves as a ligand.
- Cell signaling (cell signalling in British English) is part of any communication process that governs basic activities of cells and coordinates all cell actions. Errors in signaling interactions and cellular information processing are responsible for diseases such as cancer, autoimmunity, and diabetes.
In biochemistry and pharmacology, a ligand is a substance that forms a complex with a biomolecule to serve a biological purpose. In protein-ligand binding, the ligand is usually a molecule which produces a signal by binding to a site on a target protein.
- Medical Definition of Ligand. Ligand: A molecule that binds to another. Often, a soluble molecule such as a hormone or neurotransmitter that binds to a receptor.
- Water-soluble ligands are polar or charged and cannot readily cross the plasma membrane. So, most water-soluble ligands bind to the extracellular domains of cell-surface receptors, staying on the outer surface of the cell. Many other neurotransmitters, however, are small, hydrophilic (water-loving) organic molecules.
- A protein kinase is a kinase enzyme that modifies other proteins by chemically adding phosphate groups to them (phosphorylation). Phosphorylation usually results in a functional change of the target protein (substrate) by changing enzyme activity, cellular location, or association with other proteins.
Updated: 2nd October 2019