ADH has two actions, one on the kidney and the other on vascular smooth muscle, these actions are mediated by different receptors, different intracellular mechanisms, and different secondary messengers.

a. The major action of ADH is to increase the water permeability of principal cells in the late distal tubule and collecting duct.

b. The receptor for ADH on the principal cells is a V2 receptor, which is coupled to adenylyl cyclase via a Gs protein. 

c. The second messenger is cAMP, via phosphorylation steps, directs the insertion of water channels, aquaporin 2 (AQP2), in luminal membranes.

d. The receptor for ADH on the principal cells is a V1 receptor, which is coupled to phospholipase C via Gq protein.

Which one of the following combination of above statements is correct?

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#Question id: 15670

#Unit 8. Inheritance Biology

A researcher would like to map the location of galE and trpA genes in a new species of bacterium that appears to be closely related to E. coli. He decides to use cotransduction, and generates appropriate donor and recipient strains. He is disappointed when cotransduction is not seen in his experiement. What is the most reasonable explanation for this situation?

TLS Online TPP Program

#Question id: 15833

#Unit 8. Inheritance Biology

Your friends Ben and Jane are contemplating having children and seek your genetic counsel. Ben and Jane are unrelated, but both have younger brothers with the same, extremely rare genetic trait. (In fact, Ben and Jane met at a support group meeting for children and families of children with this rare disorder.) Ben’s parents and Jane’s parents are all unaffected.          

Assume that the trait is autosomal dominant with 80% penetrance in heterozygotes and 100% penetrance in homozygotes. If not affected, what is the probability that the child is a carrier?

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#Question id: 19108

#Unit 8. Inheritance Biology

Assume that mating is random. Colorblindness is an X-linked recessive trait that is found in about 5 percent of males. What fraction of females are heterozygous carriers of the colorblindness allele?

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#Question id: 19109

#Unit 8. Inheritance Biology

Assume that mating is random. Colorblindness is an X-linked recessive trait that is found in about 5 percent of males. What fraction of females are homozygous for the colorblindness allele?  

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#Question id: 19110

#Unit 8. Inheritance Biology

If the frequency of PKU among newborns is approximately 1/10,000 (when the parents are unrelated). What is the risk of a child with PKU if the parents are siblings?

TLS Online TPP Program

#Question id: 23567

#Unit 8. Inheritance Biology

Telomeric staining specifically detected by_____