Chapter 7: Cell Signaling Flashcards
(20 cards)
What do cells use to communicate
Proteins, Ions, small molecules and etc.
What are the three main stages of signaling
Reception, Transduction and Response
What happens in reception?
A signaling molecule binds to a protein receptor and makes it do things (membrane or in cell)
What happens in transduction?
A series of relay molecules carry a signal into a cell and amplifies the signal
What happens in response?
The signal causes changes in the cell like gene expression and protein activity
What is a ligand
The chemical signal that is received in reception (ions, proteins or small molecules)
Receptor
Protein structures that receive ligands, can be integral proteins in plasma membrane or can be in cytoplasm
What are the three main classes of protein receptors
G-protein coupled receptors, Receptor tyrosine kinases, Ion channel receptors
How do G-Protein coupled receptors work?
A ligand binds to GPCR changing its shape, A GDP leaves the GPCR and a GTP (from cytosol) takes its place activating the G-protein. The GTP binds to an enzyme activating it, the enzyme makes a messenger molecule called cyclic AMP (cAMP) initiating transduction. The GTP is hydrolyzed on its way back returning as GDP to the GPCR
Components of G-protein receptors
GPCR (receptor binding site), A membrane anchored G protein (GDP (on) or GTP (off)) and a membrane bound enzyme
What is Rhodopsin
A GPCR in rod cells that make up a retina
What is a retinal?
A molecule that binds to Rhodopsin
What are RTKs?
Receptor tyrosine kinases, monomers that make up GCPR, have binding sites outside the membrane but exist in the membrane, when they receive a signal molecule they bind together and form dimers. They then use 6ATP to become fully activated by attaching 6 phosphate groups to each of their 3 tyrosine ends. Relay proteins bind to them kicking off transduction
What is a Kinase
An enzyme that can add a phosphate group onto something
What are RTKs used for
Triggering cell division, differentiate cell types and dictate whether or not a cell kills itself
What is apoptosis
cell suicide
What are ligand gated ion channels
Receptors that control a gate, only open when a ligand is present
Transcription factors
proteins that can bind DNA at specific nucleotide sequences and turn on the transcription of specific genes
What is phosphorylation cascades?
A way which transduction occurs. Uses A chain of kinases to take phosphate from ATP and then passes it along to a protein activating the protein. When the cause for transduction is removed, all the phosphate groups are removed from every kinase and protein deactivating all of them.
What are 3 secondary messengers that also conduct transduction
cAMP(made by adenylyl cyclase), calcium ions let in by ligand gates a fuck ton more we aint gettin into
