In humans, PKU (phenylketonuria) is a recessive disease caused by enzyme inefficiency at step A in the following simplified reaction sequence, and AKU (alkaptonuria) is a recessive disease due to enzyme inefficiency in one of the steps summarized as step B here:A person with PKU and homozygous for normal of other character was married a person with AKU and homozygous for normal of other character. What is expected phenotypes in their children?

#Question id: 1136

#Unit 4. Cell Communication and Cell Signaling

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

#Unit 4. Cell Communication and Cell Signaling

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

#Unit 4. Cell Communication and Cell Signaling

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: 1139

#Unit 4. Cell Communication and Cell Signaling

In paracrine signaling, the signaling molecule:

#Question id: 1140

#Unit 4. Cell Communication and Cell Signaling

Cell sensitivity to an external signal is determined by:

#Question id: 1141

#Unit 4. Cell Communication and Cell Signaling

If [R] = the free receptor concentration and [L] = the free ligand concentration, Kd is: