Ch 9 Flashcards
Ligand
Signaling molecule
Receptor
A protein to which the ligand binds
Cytokines and chemokines
Ligand that are secreted by cells and only work on nearby cells with receptors
Four basic mechanisms for cellular communication
Direct contact
Paracrine signaling
Endocrine signaling
Synaptic signaling
Direct contact
Ligand molecules on the surface of once cell are recognized by receptor molecules on an adjacent cell
Paracrine signaling
Ligand released from a secretory cell bind to receptors on adjacent cells
Endocrine signaling
Special ligand called hormones are released from secretory cells and bind to receptors on or within cells throughout the body
Synaptic signaling
Nerve cells release the signal ligand which binds to receptors on nearby nerve or muscle cells
Signal transduction
The series of chemical reactions that occur following the binding of a ligand to a receptor
Kinase
An enzyme that adds a phosphate to a protein, thus activating it
Phosphatase
An enzyme that removes a phosphate from a protein, thus deactivating it
Where are the two types of receptors
Cell surface or membrane receptor: on the plasma membrane
Intracellular receptor: located inside cell
Three classes of membrane receptors
Channel linked or gated receptors: ion channel opens in response to ligand binding
Enzymatic receptors: receptor is an enzyme that is activated by ligand binding
G protein-coupled receptors: a G-protein assists in transmitting the signal
Receptor tyrosine kinase
An enzyme receptor
What happens to the membrane bound receptor when the signal ligand binds?
Dimerized and autophosphorylated
