Protoplasmic Streaming in Giant Algal Cells
(Genus: Nitella; Family: Characeae; common name: "stoneworts")


Wait for the animation to load completely and play through once. To stop the animation, click on the "pause" button. To see the frame that precedes the paused frame, press the "previous" button. To see the frame that follows the paused frame, click on the "next" button. To resume the animation, click on the "play" button.

1) Describe the directions and patterns in which cytoplasmic inclusions are streaming. Consult reference books that describe cellular and molecular mechanisms involved in protoplasmic streaming in this giant algal cell.
2) TRACKING: Lay a small clear transparency sheet over the animation.  Use two small pieces of paper tape to secure the corners of the transparency sheet to the monitor screen.  Use a marking pen to make a series of dots on the sheet that record the second-by-second position of a selected particle that is moving in the stream.  Make sure the the correct elapsed time is recorded for each dot. Note that there is one second of elapsed time between each frame.
3) CALCULATION: Using the distance scale that is given on the animation, calculate the velocity with which a selected particle is moving in the streaming protoplasm.  Units should be in microns/second.  [NOTE: 0.1 mm = 100 microns]
4) Do all particles move at the same velocity?  If not, explain why velocities may vary?

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Software for controlling interactive animations was developed by TOM DREWES