#Question id: 11740
#Unit 6. System Physiology – Plant
Some given characteristics of the two types of sieve elements in seed plants such as Sieve tube elements and Sieve cells. Find out the true characteristics of sieve tube elements from the given statements;
i) Found in angiosperms
ii) Sieve plate pores are open channels
iii) Albuminous cells sometimes function as companion
cells
iv) P-protein is present in all eudicots and many
monocots
v) There are no sieve plates; all sieve areas are similar
#Question id: 2805
#Unit 2. Cellular Organization
There is a roughly inverse correlation between organism complexity and gene density
#Question id: 31216
#Unit 4. Cell Communication and Cell Signaling
#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: 28205
#Unit 5. Developmental Biology
Genome of the epithelium limits its ability to respond to signals from the mesenchyme, the response is species specific is called___