Which is an experimental means that can be used to distinguish between a signal transduction pathway that uses a cell membrane receptor and one that uses an intracellular receptor?
A) Compare the ability of cells to respond to chemical signals that are similar in structure to the actual signal molecule.
B) Observe whether stimulation of the signal transduction pathway by the signal molecule can be inhibited by another molecule.
C) Incubate cells with a signal molecule containing the carbon-14 radioisotope and observe whether any carbon-14 enters cells.
D) Quantify the number of cell membrane receptors present in a single cell and compare with cell membrane receptor numbers in other cell types.
E) Determine whether the cell response involves a change in gene expression or a change in the activity of a cytosolic enzyme.

Question

Quizplus · Accepted Answer

Incubating cells with a carbon-14 labeled signal molecule and observing whether any carbon-14 enters the cells can distinguish between cell membrane and intracellular receptors. Cell membrane receptors bind to signal molecules outside the cell, so carbon-14 would not enter the cell. In contrast, intracellular receptors require the signal molecule to enter the cell, so carbon-14 would be detected inside.

Which Is an Experimental Means That Can Be Used to Distinguish