Cellular Streaming is the process of a cell guiding organelles and metabolites to a determined destination
within the cell where it is needed. In Chara cells, Streaming is facilitated by the motor protein myosin. When
chara’s cell wall is damaged, it stops streaming by deactivating myosin through a kinase-mediated
phosphorylation. This kinase is activated when excess calcium binds to it. In this lab, we will be observing what
level of calcium ions are needed to stop cellular streaming when chara is exposed to a damaging stimulus.
In order to see what concentration of calcium is needed to activate this kinase, chara cells will be placed in four
different solutions that vary in their levels of calcium concentration. Then streaming will be observed under a
dissecting microscope where a voltage is applied to damage the cell wall to initiate the flow of calcium into the
cell. The observable halt of streaming after electrical stimulation will be used to determine if the solution’s calcium
concentration is sufficient to activate kinases that deactivate myosin. The use of electricity to increase calcium
concentration and halt cellular streaming is called EC-coupling.
Sample Solution
