Chapter Nine: Cell Communication Flashcards
Cell signaling involves both ___________ and ___________ signals
incoming and outgoing
Any agent that can influence the properties of cells
A Signal
Signals are recognized by…
Receptors
What are allosteric and cause a cellular response?
Receptors
What type of signaling?
- cell junctions may allow signals to pass directly between cells
- Gap junctions would be an example
Direct Intercellular Signaling
What type of Signaling?
One cell has a membrane-bound signal recognized by a receptor by a receptor on another cell
Contact-dependent Signaling
What type of Signaling?
Cell Secretes a signal/chemical that bind to receptors on their own surface and that of neighboring cells of the same type, stimulating them
Autocrine Signaling
What type of signaling?
Cell Secretes a signal that influences not themselves but target cells in close proximity
Paracrine Signaling
What type of cell signaling?
Cell secretes a hormone into bloodstream that affects cells far from the source of the signal
Endocrine Signals
What are the three step response to signals?
- Receptor Activation
- Signal Transduction
- Cellular Response
The _________ ____________ binds to the Receptor causing a conformational change in the Receptor which activates its function
signaling molecule
Most signals are ______________ and can not enter cells through the membrane
hydrophilic
The initial signal is converted to a second signal _____________ the cell
inside
Many signals activate _____________ inside the cell
enzymes
Some signals alter the ___________ of structural proteins in the cell
function
Some signals affect _________ that bind to and regulate the activity of genes directly
proteins
What are signals that bind non-covalently and temporarily to Receptors?
Ligands
What changes the receptor to activate the ability to initiate the cellular response?
binding
Is binding temporary and reversible?
yes
When the _________ is released, receptor is no longer activated
ligand
The signal, often a _____________, binds the receptor
hormone
Receptors have different ______________ for the signal
affinities (preferences)
The Dissociation Constant (___) indicates the affinity
Kd
A low Kd indicates a ________ affinity
high
Receptors are necessary because most signals are hydrophilic or large molecules that will not diffuse through the…
Plasma Membrane
Cells need _________ receptors to bind specific signals
surface
Enzyme-linked receptors have a receptor in the ____________ _________ where the signal, often a hormone, bonds
Extracellular matrix
The _______________ ____________ has a catalytic function
Intracellular Domain
When the Extracellular Domain is bound, the ________________ _____________ is activated
Intracellular Domain
Most Enzyme-linked receptors have a protein ____________ function in the intracellular domain
Kinase
When bound by a signal, the protein kinase will ______________ other proteins
phosphorylate
Protein Kinases ____________ a phosphate from ATP and attach it to a protein
remove
The phosphorylated protein is usually _____________ to cause a cellular response
activated
G Proteins are named for their ability to bind _______ as a substrate
GTP
The receptors typically have _____ transmembrane segments which embed it in the Plasma Membrane
7
G Proteins have what two subunits?
alpha and beta
When bound by a signal, the receptor’s intracellular domain causes the G protein to release _______ and bind ________
GDP
GTP
When bound to the GTP, the ___ subunit dissociates from the ____ subunit
alpha
beta
After the alpha subunit dissociates from the beta subunit, it is then _______ and free to initiate a cellular response
active
That alpha subunit splits GTP to GDP, which allows alpha to be bound by the beta subunit, ____________ the G protein, ending the cellular response
inactivating