The insulin signaling pathways involves binding of insulin to its receptor, leading to the eventual insertion of glucose transport proteins (GLUTs) into the cell membrane. In a cell that does not respond properly to insulin, scientists find that following exposure to insulin various intracellular proteins are phosphorylated, but there is no increase in the amount of GLUTs on the cell surface. The most likely explanation for this is that
A) signal transduction is working, but there is a problem with receptor binding and activation
B) receptor binding and activation and signal transduction are both working
C) receptor binding and activation is working, but there is a problem with signal transduction
D) receptor binding and activation and signal transduction are both not working

Question

Quizplus · Accepted Answer

The phosphorylation of intracellular proteins suggests that signal transduction is occurring, but the lack of GLUTs on the cell surface suggests a problem with the downstream action of insulin. Therefore, the problem is most likely with signal transduction, while receptor binding and activation are functioning properly.

The Insulin Signaling Pathways Involves Binding of Insulin to Its