Prof Gray - Done Flashcards
Why is it important to coordinate behaviour between cells?
to ensure that a response to a stimulus involves the cells working together
What is endocrine signalling?
use of hormones to signal via the bloodstream
what type of signalling system does insulin belong to?
endocrine
what type of cells receive signals from the endocrine system?
all cells, only some respond
what scale is paracrine signalling on?
neighbouring cells only
what are histamine and nitric oxide examples of?
paracrine signalling
what type of cells use neuronal signalling?
neurones
where are neuronal signalling molecules released?
synapses between neurones
what is acetylcholine an example of?
neuronal signal
what is a key feature of a single type of neurotransmitters?
they can be used for more than one response
Where are direct contact signals?
in the PM
what is a delta signal a type of?
direct contact signal
how do intracellular signals work?
the signal diffuses through the PM of the cell
name the 2 types of intracellular activity?
enzyme activity and gene expression
how do intracellular receptors impart activity on an enzyme?
binding changes 3D conformation
Name an example of an intracellular signal which imparts enzymatic activity?
Nitric oxide
How is the nitric oxide pathway utilised in viagra?
NO binds to enzyme stimulating cGMP production
How can intracellular receptors regulate gene expression?
Travel through PM and bind to receptor allowing DNA binding
What allows ligand gated ion channels to open and close?
signal binding/un-binding changes the 3D conformation
Where are ligand gated ion channels commonly used?
neurone synapses
Kinases impart enzymatic function on membrane proteins, how is this done?
Dimerisation takes place
How many passes across the membrane take place in G protein receptors?
7
What is the result of the signal binding to a G protein couple receptor, in terms of the G protein?
The receptor allows the G protein to bind to GTP
What does the G protein do when bound to GTP and released rom the receptor?
It binds to an effector enzyme activating it
What does the Ras protein bind to allowing activation of a kinases cascade?
GTP
What type of enzyme is Ras?
GTPase
what is the result of a protein kinase cascade?
cell proliferation
When is Ras switched off?
when GTP is broken down to GDP
Why can mutant forms of Ras result in cancerous cells?
They are not GTPases meaning that cell proliferation is not switched off
What does Phospholipase C produce as a secondary messenger?
PIP2/IP3 (same thing)
How does PLC make PIP2?
cleaves a membrane lipid
When PIP2 binds to its receptor what effect takes place?
Ca2+ are released allowing further activation of enzymes
What does GPCR stand for?
G protein coupled receptors
What is a common secondary messenger for GPCRs?
cAMP
What does cAMP production usually lead to the activation of?
Protein kinase cascade
If a process leads to the production of one signal and the activation of an enzyme, why might a totally different enzyme also be activated?
Signalling pathways are heavily cross linked
