Refer to the figure and table below. A researcher treated mouse kidney cells growing in culture so that they took up a fluorescent dye into their cytosols without losing viability.(This dye undergoes a change in fluorescence intensity upon binding calcium ions.) The treated cells were then incubated with and without a compound thought to act as a signaling molecule, and the cells were observed for changes in fluorescence.The researcher hypothesizes that the signaling molecule functions according to the pathway shown in the diagram above.As a next step, the researcher wants to acquire evidence that IP₃ is involved in this pathway.Which procedure will provide needed evidence about IP₃ as the entire experiment is repeated? A) Using mouse kidney cells containing a mutation that knocks out GTP binding by G protein B) Using mouse kidney cells containing a mutation that knocks out phospholipase C C) Adding a calcium channel inhibitor during all trials D) Replacing the signaling molecule with an agonist molecule E) Replacing the signaling molecule with IP₃

Question

Quizplus · Accepted Answer

To provide evidence that IP₃ is involved in the pathway, the best choice would be to use mouse kidney cells containing a mutation that knocks out phospholipase C. This is because IP₃ acts as an activator of phospholipase C, and if phospholipase C is knocked out, there should be no response to the signaling molecule or IP₃. The other options may affect other parts of the pathway and not specifically test the involvement of IP₃.

Refer to the Figure and Table Below