CCR5 that plays a role in inflammatory response. Unfortunately, this protein is also a key to human immunodeficiency virus (HIV) infection. The virus binds to a loop of the CCR5 protein and then enters the cell. Some people have an allele called Δ32 at the CCR5 locus in which 32 bp are deleted. The missing part of the gene codes for the loop in the protein to which the virus attaches. Which statements is true for CCR5?

#Question id: 526

#Unit 1. Molecules and their Interaction Relevant to Biology

Which substance causes muscles to ache during strenuous exercise?

#Question id: 1255

#Unit 4. Cell Communication and Cell Signaling

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?

#Question id: 21246

#Unit 7. System Physiology – Animal

#Question id: 15777

#Unit 5. Developmental Biology

#Question id: 23468

#General Aptitude