Cell Communcation Flashcards
Essential elements for cell communication-
Signalling cell
Grow+Divide
Differentiate
Die
In bacterial cells, the signalling peptide binds to the receptor to uptake DNA when…
Population density is high
4 steps in cell signalling
- Receptor activation
- Signal transduction
- Response
- Termination
The signal binds to a receptor, which is activated
Receptor activation
Signal is transmitted to the interior of the cel by a signal transduction pathway
Signal transduction
The cell responds
Response
The cell is terminated so that new signals can be received
Termination
Signalling molecules through he bloodstream over distance
ENDOCRINE
Involves cell communication close to eachother, short distance to the neighbouring cells receptor
PARACRINE
Signalling cell and responding cell are the same.
-Embryology
AUTOCRINE
Uses direct contact between neighbouring cells in absence of signalling molecule
CONTACT-DEPENDENT
Small nonpolar signalling molecules can pass freely through the plasma membrane and activate cytoplasmic receptor
Intracellular receptors
A receptor molecule undergoes a ….., activating a receptor
Conformational change
When a G protein is bound to GTP
ACTIVE
When a G protein is bound to GDP
INACTIVE
When a ligand binds to a G protein-coupled receptor, it activates the G protein by…
Replacing GDP—-> GTP
Enzyme that adds a phosphate group to another molecule
Kinase
When a protein is phosphorylated
Active
Alter the flow of ions across the plasma membrane
Ion channels
G proteins are composed of…
Alpha
Beta
Gamma
When 3 subunits are joined….
G protein INACTIVE
What causes b to separate from gamma?
GDP ——> GTP
GTP- bound alpha subunit…
ACTIVE
Adrenaline is amplified in 3 places…
1) Adrenaline bound receptor activates multiple G proteins
2) Each adenylyl cyclase produces cAMP
3) Each kinase A activates multiple protein targets
Terminating G protein involves…
Converting GTP——>GDP
Phosphataeses
Remove phosphate groups from activated proteins=inactive
Used in formation of limb buds, insulin signalling and would healing
Receptor Kinase
Responsible for pigment in skin, feathers, hair extensions…
Kit
Dimerization
Receptor Kinase
Single signalling molecule binds with extracellular protein with 2 receptors
Causes receptors to pair
Activates the cytoplasmic kinase domains to cause phosphorylation to the tails
Dimerzation
Phosphorylated areas provides a place for proteins to…
Bind and become active
MAP Kinase Pathway steps (5)
- PDGF and platelets released. PDGF bind to PDGF receptor kinases and dimeraze to become active
- phosphorylated receptors signal other proteins
- Ras activates
- Kinases enter nucleus to regulate transcription
- GTP—->GDP inactive
30% of cancer mutation due to…
Ras
…. can take place at every step of cell communication
Cancer
