#Question id: 4114
#Unit 3. Fundamental Processes
Splice-site recognition is prone to two kinds of errors. First, splice sites can be skipped, with components bound at, for example, a given 5’ splice site pairing with those at a 3’ site beyond the correct one. Ways in which the accuracy of splice-site selection can be enhanced are as
A. The factors that recognize that site are transferred from the polymerase carboxy-terminal “tail” onto the RNA. Once in place, the 5’ splice site components are poised to interact with those other factors that bind to the next 3’ splice site to be synthesized.
B. SR (serine–arginine-rich) proteins bind to sequences called exonic splicing enhancers (ESEs) within the exons. SR proteins bound to these sites recruit the splicing machinery to the nearby splice sites to ensure correct splicing
C. By recruiting splicing factors to each side of a given exon, this process encourages the so-called “exon definition, contribute to correct splicing
D. Alternative splicing is intentional missplicing mechanism
Which of the following is INCORRECT?
#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: 9200
#Unit 9. Diversity of Life Forms
During the inventory of bacterial genes present in the Sargasso Sea, a deep isolated area in the middle of the Atlantic Ocean, a research team concluded that at least 1,800 bacterial species were present. Based on what you might predict about the habitat structure of such an area, what kind of bacterial diversity would you expect to see in tropical coral reef waters?
#Question id: 5267
#Unit 8. Inheritance Biology
The F plasmid carries the information for
#Question id: 6980
#Unit 5. Developmental Biology
Teeth form from