Chapter 11 Flashcards
A received signal is converted to a specific cellular response in a series of steps
Signal transduction pathway
Signaling molecules sensed by bacteria allows them to monitor the local density of cells
Quorum sensing
Discharges a regulator in extracellular fluid
Paracrine
Cell surface transmembrane
G protein-coupled receptor
Binds energy rich molecule GTP
G protein
Makes the G protein inactive
GDP
What activates a G protein?
When a signaling molecules binds to the receptor
Why are GTPase enzymes important?
Hydrolyzes GTP to GDP causing the G protein to be inactivated and be reused again
Catalyzes the transfer of phosphate groups from ATP to the amino acid tyrosine on a substarate protein
Kinase enzyme
How does tyrosine kinase function?
Attach phosphates to tyrosine
What is the difference between receptor tyrosine kinases and G protein-coupled receptors
Tyrosine kinases trigger many pathway while G-proteins receptors do not
Control what genes are transcribed into mRNA in a particular cell
Transcription factors
Transfers phosphate groups from ATP to a protein
Protein kinase
Remove phosphate groups from proteins
Protein phosphatases
Ligand binding to membrane receptors
1st messenger
Water soluble molecules that spread through the cell by diffusion
2nd messenger
what is the role of cAMP?
Activates another protein
What is the important relationship between the second messenger and protein kinase A?
cAMP activates kinase A which leads to cellular responses
When cell signaling causes a nuclear response, what normally happens?
Specific genes are turned on or off
Large relay proteins that several other proteins are attached to it
Scaffolding proteins
The dying cell leaks out its contents; death of a cell
Apoptosis
Chemical message binds to a protein on the cell surface
Reception
Binding of the ligand to the receptor, stars a cascade of reactions
Transduction
What kinds of responses do cells have?
Turning on/off genes, activating enzymes, rearranging cytoskeleton
What are the 3 types of receptors?
G-protein coupled, tyrosine kinase, ion gated channels
What are the 2 types of 2nd messenger?
Calcium, cAMP
