Question

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Following graphs, the cellular response, as measured in real time by the concentration of a certain active effector protein, is plotted over time for five cell types (A to E) that are treated with three different concentrations of a signal molecule. During the time period indicated by the horizontal gray bar. the signal molecule is present in the culture media at a concentration of 1 nM (dotted curve), 5 nM (gray curve), or 25 nM (solid curve). Answer the following question(s) based on these graphs. Which of the cell types A to E shows the lowest sensitivity to the signal? Which of the cell types A to E shows a response with the highest persistence? Which of the cell types A to E shows the fastest signal adaptation? Which of the cell types A to E shows the widest dynamic range of signal concentration? A cell expresses a trans membrane protein that is cleaved at the plasma membrane to release an extracellular fragment. The fragment binds to receptor proteins on nearby cells and activates signaling pathways resulting in altered gene expression patterns in the cells. What form of intercellular signaling does this represent? What action normally activates a G-protein? What type of protein catalyzes this activity?

Answer 1

lowest sensitivity-E

highest persistence- D

fastest signal adaptation- A

dynamic range of signal concentration- C

5. this represent a paracrine mode of intercellular signalling

6 when a ligand binds to a G-protein coupled receptor GDP/GTP exchange occurs which activates a G-protein