In certain motile prokaryotes, dozens of different proteins comprise the motor that powers the prokaryotic flagellum. The motor has a complicated structure, and its various proteins interact to carry out its function. Based on Darwinʹs explanation for the existence of human eyes, how would he probably have explained the existence of such motors?

#Question id: 1245

#Unit 4. Cell Communication and Cell Signaling

Many PTB-containing proteins act as docking sites for multiple proteins. If these proteins are involved in the RTK signal transduction pathway, they most likely:

#Question id: 1246

#Unit 4. Cell Communication and Cell Signaling

An SH2-containing protein contains a mutation that changes its binding pocket such that tyrosine and phosphotyrosine bind with equal affinity. As a result, MEK activity:

#Question id: 1247

#Unit 4. Cell Communication and Cell Signaling

Which of the following is NOT true about the role of adapter proteins in the activation of Ras by receptor tyrosine kinases?

#Question id: 1248

#Unit 4. Cell Communication and Cell Signaling

By what mechanism does PI-3 phosphate promote activation of protein kinase B (PKB)?

a. recruiting PKB to the plasma membrane

b. recruiting the activating kinase PDK1 to the plasma membrane

c. releasing inhibition of the catalytic site by the PH domain

d. by the activation of FOXO3A

#Question id: 1249

#Unit 4. Cell Communication and Cell Signaling

As in all G protein–coupled signalling pathways, timely termination of the rhodopsin signalling pathway requires that all the activated intermediates be inactivated rapidly, restoring the system to its basal state, ready for signalling again. Which of the following mechanism does not terminate rhodopsin signalling?

#Question id: 1250

#Unit 4. Cell Communication and Cell Signaling

Few mutants (column A) and their results (column B) are listed in the table given below:

Match the correct mutation with the observe result?