Unit 4a - Cell Communication Flashcards
Autocrine Signaling
Cell signals itself
Juxtacrine Signaling
Two cells are in contact w/ one another
Paracrine Signaling
Two cells that are close but not touching
Endocrine Signaling
When ligands travel long distances to signal
What are the 3 steps of cellular signaling
Reception
Transduction
Response
Reception
Detection of a ligand coming from outside the cell
Transduction
Converting a signal to a form that can bring about a response
Response
Cellular response to the signal molecule
Ligand
Signaling molecule that binds w/ a receptor.
What are the two types of receptors
Plasma Membrane
Intracellular
What happens in the FIRST step of a G-protein Receptor reaction?
The G protein has an inactive GDP.
What happens in the SECOND step of a G-protein Receptor reaction?
The ligand bonds to the receptor and the protein bonds to the receptors. The protein exchanges a GDP for a GTP.
What happens in the THIRD and FOURTH steps of a G-protein Receptor reaction?
The ligand unbinds w/ the receptor ; the protein (w/ GTP) binds with an enzyme and a cellular response occurs ; the GTP is turned to a GDP.
What happens in the FIRST step of a Tyrosine Kinase Receptor reaction?
A ligand is introduced near the inactive receptor.
What happens in the SECOND step of a Tyrosine Kinase Receptor reaction?
Ligands bind w/ the tyrosine kinase –> A dimer is created when the two kinase bind together.
What happens in the THIRD step of a Tyrosine Kinase Receptor reaction?
Six ATP give up one phosphate to the 6 tyrosine molecules on the kinase , becoming ADP.
What happens in the FOURTH step of a Tyrosine Kinase Receptor reaction?
Multiple cellular responses occur.
What happens in the FIRST step of Ligand Gated Ion Channel?
The receptor is closed w/o an ligand to bind and open it.
What happens in the SECOND and THIRD steps of a Ligand Gated Ion Channel?
The ligand binds to the receptor and the gate opens –> a cellular response occurs –> ligand detaches and the gate closes.
What is the structure of the G-Protein Coupled Receptor?
7 transmembrane segments.
Cascades
Relay signals from receptor to target molecule.
What is the structure of the Ligand Gated Ion Channel Receptor?
Signal on receptor changes shape ( to regulate the flow of specific ions)
Protein Kinase
Enzyme that phosphorylates and activates proteins at the next level.
Phosphorylation Cascade
Enhance and amplify signals
Second Messenger
Small , non-protein molecules/ions that can relay signal inside the cell.
What are the types of Transduction?
Cascades
Protein Kinase
Phosphorylation Cascade
Second Messengers
Apoptosis is in what step of Cellular Signaling?
Response
What is Apoptosis?
Cell Suicide
- cell is dismantled and digested
- triggered b signals that activated a cascade of “suicide” proteins
Why to cells do Apoptosis?
- Protect neighboring cells from damage
- Animal development and maintenance.
