A feature of RNA that adds to its propensity to form double-helical structures is additional non-Watson–Crick base pairs. One such example is the G:U base pair, which has

#Question id: 1134

#Section 3: Genetics, Cellular and Molecular Biology

Arrange the following proteins in the proper order in which they become activated in the MAPK signaling pathway:

a. MAP kinase                         b. MEK           c. Ras              d. Raf              e. RTK            

#Question id: 1136

#Section 3: Genetics, Cellular and Molecular Biology

Which of the following signaling pathways can be activated by activation of receptor tyrosine kinases?

a. phospholipase Cγ                b. PI-3 kinase

c. MAP kinase                         d. none of the above

#Question id: 1137

#Section 3: Genetics, Cellular and Molecular Biology

A loss-of-function mutation in PTEN phosphatase results in

a. increased cell proliferation.            

b. decreased cell proliferation.

c. increased apoptosis.                                   

d. decreased apoptosis.

#Question id: 1138

#Section 3: Genetics, Cellular and Molecular Biology

A loss-of-function mutation in Wnt would have a phenotype similar to a

a. gain-of-function mutation in GSK-3.                    

b. gain-of-function mutation in β-catenin.

c. loss-of-function mutation in GSK-3.                     

d. loss-of-function mutation in β-catenin.

#Question id: 1140

#Section 3: Genetics, Cellular and Molecular Biology

Cell sensitivity to an external signal is determined by:

#Question id: 1142

#Section 3: Genetics, Cellular and Molecular Biology

Of the components of a heterotrimeric G protein, which subunit(s) is(are) able to activate downstream responses?