Cell Signaling Flashcards
Communication between cells in a
multicellular organism is a critical function
of life
cell signaling
Type of Signaling:
signaling between adjacent cells
juxtacrine signaling
Type of Signaling:
signaling between nearby cells
paracrine signaling
Type of Signaling:
signaling between distance cells
endocrine signaling
who can respond to signals?
Only cells with a receptor tuned to the
specific signal can respond to the signal
What is responding to signals?
changing some cellular signaling
-enzyme activity
-gene expression
-cell division
Reception:
most chemical signals are ____
hydrophilic
Hydrophilic signals can’t pass the membrane without help, which means…
most receptors are integral transmembrane proteins
Transmembrane proteins function on ____ sides of the membrane
both
Types of Chemical Signaling:
-Pass through the plasma membrane and bind a specific receptor in the cytoplasm or in the nucleus
-Activated Receptor–Ligand Complex
regulates genes by binding to DNA
Lipid-Soluble Signals (hydrophobic)
- Receptors found in the cytoplasm or in the nucleus
- Signal must be primarily hydrophobic or very small to diffuse through the membrane.
intracellular signaling
Types of Chemical Signaling:
-Cannot pass through the membrane
– Bind to specific plasma membrane receptors
– The Receptor–Ligand Complex activates a cascade of events in the cell
Water-Soluble Signals (Hydrophilic)
Signal must be
hydrophilic and thus
unable to diffuse through
the membrane.
membrane-bound receptors
-Ligand-Gated Ion Channel
-G Protein-Coupled Receptor
-Enzyme-Linked Receptor
Type of Membrane-Bound Receptors
Type of Membrane-Bound Receptors:
a ligand (ex: ACh) binds to a receptor, which then opens to let ions through
Ligand-Gated Ion Channel
Type of Membrane-Bound Receptors:
a receptor is coupled with a G-protein, which is activated and causes a cascade of signaling in the cell
G-protein Coupled Receptor
Type of Membrane-Bound Receptors:
an enzyme (ex: insulin receptor) after signaling molecule binding can catalyze other molecules (substrates) which allows for cellular responses
Enzyme-linked receptor
-Reception of a signal triggers a series of
steps that eventually leads to a
biochemical response
-pathway of changes
signal transduction pathway
Signal Transduction:
The most common regulatory step is
the addition or removal of a
____
Phosphate Group
Adding Phosphate
Phosphorylation
Phosphorylation:
General name for an
enzyme that adds a phosphate group from ATP to a protein
protein kinase
Removes phosphate
protein phosphatase
Reverses the action of the kinase
- Returns protein to its original conformation
– Allows protein to be reused
- In cells, there is a balance between kinase activity
and phosphatase activity
protein phosphatase
activated by the initial signal (First
Messenger) and carry instructions
through the cell
second messengers
