6. Signal Transduction Flashcards
What are the three stages of cell signaling?
Reception, Transduction, Response
What are the three major goals of the cell signaling process?
Coordinate activities, Regulate behavior, Trigger appropriate responses
Name the types of receptors used in signal transduction.
- G-protein linked receptors
- Tyrosine kinase receptors
- Ligand-gated ion channels
- Integrins
- Toll-like receptors
What is a signal-transduction pathway?
The process by which a signal on a cell’s surface is converted into a specific cellular response
What is the role of ligands in cell signaling?
Small molecules that bind specifically to larger molecules, typically receptors
True or False: Most signal molecules are water-soluble and can pass through the plasma membrane directly.
False
What is the function of G-protein-linked receptors?
They consist of a receptor protein associated with a G-protein on the cytoplasmic side and act as on-off switches
What happens when GDP is bound to a G protein?
The G protein is inactive
What is the role of tyrosine-kinase receptors?
Regulate and coordinate a variety of activities and trigger several signal pathways at once
How do ligand-gated ion channels function?
They open or close in response to a chemical signal, allowing or blocking ion flow
What are integrins?
Transmembrane receptors that facilitate cell-extracellular matrix adhesion
What are the typical ligands for nuclear receptors?
Non-polar hormones like steroid hormones
What is a phosphorylation cascade?
A series of events where one protein kinase activates another, amplifying the signal
What is the primary role of protein phosphatases?
To turn off a signal-transduction pathway by removing phosphate groups from proteins
Fill in the blank: The process of _______ is crucial for regulating protein activity in cell signaling.
Phosphorylation
What are second messengers?
Small, nonprotein, water-soluble molecules or ions that participate in signaling pathways
True or False: The response of a cell to a signal depends solely on the signal itself.
False
What is the significance of multi-step pathways in signal transduction?
They amplify the signal and contribute to the specificity of the response
What is the function of cyclic AMP in signal transduction?
It acts as a second messenger that relays signals within the cell
What happens to cyclic AMP when the extracellular signal is absent?
It is rapidly hydrolyzed by phosphodiesterases
What is apoptosis?
A form of programmed cell death that occurs when a cell is deprived of appropriate survival signals
What is the role of phosphorylation in signaling?
Phosphorylation activates signaling by adding a phosphate group and is inactivated by removal of the phosphate.
What are second messengers?
Small, nonprotein, water-soluble molecules or ions that rapidly diffuse throughout the cell.
Name two important second messengers.
- cyclic AMP
- Ca2+
What is the function of scaffolding proteins in signaling pathways?
They physically link signal pathways together, enhancing speed and success of signal transfer.
What are the three major goals of the cell signaling process?
- To convey information
- To regulate cellular responses
- To coordinate cellular activities.
Compare the types of receptors used in signal transduction.
- Extracellular (G-protein linked, tyrosine kinase, ligand-gated ion, others)
- Intracellular
What are the benefits of multi-step pathways in signaling?
They allow for greater control, amplification of signals, and fine-tuning of cellular responses.
Define contact-dependent signaling.
Signaling that requires cells to be in direct membrane-membrane contact.
What is paracrine signaling?
Signaling that depends on signals released into the extracellular space acting locally on neighboring cells.
Describe synaptic signaling.
Performed by neurons transmitting signals electrically along axons and releasing neurotransmitters at synapses.
What is endocrine signaling?
Signaling that depends on endocrine cells secreting hormones into the bloodstream for wide distribution.
Fill in the blank: _______ is a secondary messenger that can also be used in signaling pathways.
IP3
True or False: Scaffolding proteins enhance the efficiency of signal transfer.
True
What are the four forms of intercellular signaling?
- Contact-dependent signaling
- Paracrine signaling
- Synaptic signaling
- Endocrine signaling
