Lecture 1 - Cell Biology Flashcards
How long does protein synthesis take?
Between 2-24 hrs
What determines cell function
Protein composition
Do steroids pass easily through membrane?
Yes, they are lipids and are thus lipid soluble
Mechanism by which lipid-soluble hormones affect cell function?
Enter the through the lipid membrane, bind to receptors which bind to DNA and regulate mRNA synthesis. The protein synthesis then takes place, which is slow (2-24 hrs)
Can water soluble molecules pass through the membrane?
No. Must bind to surface receptor which affects ion channels, coupling proteins, etc.
What produces cAMP from ATP?
What breaks cAMP down?
Adenylyl Cyclase - enzyme
Phosphodiesterase
How does cAMP regulate function of cell?
Directly
Also by activating cAMP-dependent protein kinase that phosphorylates other proteins
Adenylyl Cyclase System consists of two what?
G-proteins. Gs and Gi
Gs stimulates system
Gi inhibits
What does Phospholipase A2 do?
Cuts phospholipids to release arachidonic acid from glycerol backbone
What is arachidonic acid converted to?
Many active metabolites
What are arachidonic metabolites involved in?
pain, temperature regulation, allergies, asthma, inflammation
What do COX inhibitors do?
Decrease inflammation by inhibiting metabolite production
What’s a down side to COX inhibitors?
They may cause asthma.
If you block COX, then more lypoxygenase metabolites are formed, which may cause asthma. lypoxygenase is one of the three arachidonic acid breakdown paths.
What is used to treat asthma?
Lipoxygenase inhibitors.
Also used to treat hay fever and allergies.
What does PLC hydrolyze and what does that hydrolysis produce?
hydrolyzes PIP2
produces: diacylclycerol and IP3 (inositol 1,4,5-triphosphate)
What is diacylglycerol?
A metabolite that activates PKC (protein kinase C) which phosphorylates many proteins.
PKC is what and is especially important in what?
Protein kinase C
regulation of cell replication and/or transformation
What does IP3 do?
releases Ca++ from places and causes calcium to enter into the cell, which changes cellular activity
How does insulin work?
Causes autophosphorylation of a tyrosine kinase, which in turn causes uptake of glucose into the cell
JAK/STAT Pathway happens by what machinery?
Tyrosine Kinase
What is a substance that binds to a receptor and activates it?
A receptor agonist
An example is acetylcholine
What is a substance that binds to a receptor, but has no effect on the cell?
A receptor antagonist or receptor blocker.
An example is interleukin-1
