Module 21 Terms - Signal Transduction Flashcards
What are the 2 broad groups of signaling molecules?
Hydrophobic polar and hydrophilic nonpolar signaling molecules
What are the 3 groups of receptor proteins that bind HYDROPHILIC signaling molecules?
G protein-coupled receptors, receptor-protein kinases, and ligand-gated ion channels
Amplification
Increase in volume of an original message
G protein-coupled receptor
A type of receptor protein that, when activated, uses a molecule called a G protein as a part of the signal transduction pathway
Second messenger
An intermediate signaling molecule that amplifies the response inside the cell
Kinase
An enzyme that, when activated, catalyzes the transfer of a phosphate group from ATP to proteins
Signaling cascade
When a small amount of signal is amplified to produce a large cellular response
Receptor-protein kinase
Have a ligand-binding part outside the cell and a kinase section of the receptor on the inside of the cell. Works in a similar way to G protein-coupled receptors, except the receptor and kinase are coupled
Ligand-gated channel
A receptor protein that includes a membrane-spanning channel that opens or closes (is gated) in response to binding a signaling molecule
How do hydrophobic signaling molecules deliver their signal?
They are hydrophobic, which allows them to diffuse through lipid cell membranes to receptors floating in the cytoplasm
What is the key difference between the responses produced by hydrophobic and hydrophilic signaling molecules?
Hydrophilic signaling molecules produce short-term effects that quickly wear off (an example being adrenaline) while hydrophobic signaling molecules cause changes in gene expression, producing long-term effects (an example being testosterone)
