12. Signalling Pathways in practise Flashcards
1
Q
where are smells detected within the nasal cavity
A
the olfactory epithelium
2
Q
what type of receptors are involved in smell perception
A
GPCRs
3
Q
describe the odorant perception signalling pathway:
A
- odorant molecule interacts with the GPCR
- activates a G-protein which exchanges GDP for GTP
- Alpha subunit of GTP associates with adenylate cyclase
- adenylate cyclase converts ATP into cAMP
- cAMP activates cation channels = depolarisation
- calcium also enters the cell activation an anion channel = allows chloride efflux
- further depolarisation
4
Q
where is calcium-ABA signalling important
A
in guard cells
5
Q
what does ABA induce
A
an increase in cytosolic calcium levels
6
Q
how does calcium work to depolarise the membrane
A
inhibits K+ channels
inhibits H+ ATPase - no longer pumping out cations
activate anion channels =anion efflux
activates vacuole K+ channels = potassium efflux from the vacuole into the cytosol
7
Q
what repolarises the membrane
A
depolarisation activates K+ channels that allow K+ to leave the cell
