Which of the following is a mechanism for down regulation of signaling from G protein-coupled receptors?

a. a change in the Kd of the receptor-hormone complex

b. proteolysis of the Gα subunit                     

c. hydrolysis of cAMP to 5´-AMP

d. dephosphorylation of adenylyl cyclase

TLS Online TPP Program

#Question id: 19106

#Unit 8. Inheritance Biology

Assume that mating is random. First, consider an autosomal recessive disease that is usually lethal in childhood, and that has an incidence among newborns of 1/3000. What mutation rate would be required to maintain this frequency in the population? 

TLS Online TPP Program

#Question id: 19107

#Unit 8. Inheritance Biology

Assume that mating is random. First, consider an autosomal recessive disease that is usually lethal in childhood, and that has an incidence among newborns of 1/3000.  Perhaps the explanation for the incidence of the disease is heterozygote advantage. How large would this heterozygote advantage have to be (assuming the mutation rate is negligible)? 

TLS Online TPP Program

#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?

TLS Online TPP Program

#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?  

TLS Online TPP Program

#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: 19111

#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 uncle and niece?