Signaling Transduction Pathways Flashcards
Find examples of second messengers.
CAMP/cGMP
Calcium ion
Inositol 145 triphosphate
Diclyglycerol
How does binding GTP control the activity of G proteins?
GTP activates other proteins in the cell.
List the advantages of having second messengers in signaling pathways.
Rapid change in concentration, Amplification, Redundant in multiple signaling pathways. Crosstalk, compensation, fine regulation, or misinterpretation.
How does the binding of a hormone to a receptor activate a G-protein?
It causes an exchange of GTP for bound GDP
What are the two messenger products formed by cleavage of PIP2?
PDK1 to Akt
Cross-phosphorylation is possible when two receptor proteins with kinase domains form _______.
Dimerization arm (dimers)
Describe the mechanism of activation of heterotrimeric G proteins.
Activated when they bind GTP. Spontaneously remove phosphate (reset themselves).
First: GTPase (removes phosphate) at alpha subunit.
Second and third: ligand dissociates, signal terminates, g protein reset
The enzyme responsible for induction of the phosphoinositide cascade is ______.
Phospholipase C
Which signaling molecules stimulates a rise in cytosolic Ca+2?
Cytosolic Ca2+is controlled by organellar sequestration. Pumped out of the cell or into the ER & mitochondria.
What is the source for this Ca2+ (where is it stored)?
The endoplasmic reticulum.
In which individual are fatty acids starting to be used to generate energy for the human body?
Individual with depleted liver glycogen (early starvation.
hich organelle is primarily responsible for producing energy from fatty acids?
Mitochondria
What is NOT true regarding fatty acid transport to mitochondrial matrix?
Fatty acyl groups that enter the matrix are not committed to oxidation to acetyl-CoA.
What is correct about the beta-oxidation of fatty acids?
Two carbon molecules that then enter the citric acid cycle.
Which of the collowing is correct about the beta-oxidation of fatty acids?
Krebs cycle as acetyl-coa
