Following statements are regarding to the mechanism of action of cholera toxin.

A. cholera toxin is a homodimeric protein, target G proteins, interfering with normal signaling in host cells.

B. cholera toxin associates with a small G protein, known as ARF6.

C. association with ARF6 activates cholera toxin, which catalyzes the transfer of ADP-ribose from NAD+ to the critical Arg residue in the P loop of the alpha subunit of Gs.

D. ADP-ribosylation blocks the GEF activity of Gs and thereby renders Gs permanently inactive.

E. This results in continuous activation of the adenylyl cyclase of intestinal epithelial cells, chronically high cAMP, and active PKA dephosphorylates the CFTR Cl- channel and a sodium-proton exchanger in the intestinal epithelial cells.

Which of the following combination is correct?

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#Question id: 1312

#Unit 4. Cell Communication and Cell Signaling

In anchoring junctions, cadherins are linked to:

TLS Online TPP Program

#Question id: 2824

#Unit 2. Cellular Organization

Plant mitochondrial DNA

a. is the same size as human mitochondrial DNA.

b. encodes a 5S mitochondrial rRNA.

c. contains multiple copies that recombine with each other.

d. uses the standard genetic code.

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#Question id: 4979

#Unit 11. Evolution and Behavior

The dicynodonts that survived the Permian extinction would initially have had to endure (or escape from) the physical effects of __________, and subsequently, the biological effects of __________.

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#Question id: 2349

#Unit 2. Cellular Organization

A liver cell would detect the presence of insulin by

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#Question id: 2159

#Unit 2. Cellular Organization

A channel protein