PhET-Simulations-for-Biology/C3/Membrane-Channels/English-timed

Time	Narration
00:01	Welcome to this spoken tutorial on Membrane Channels PhET simulation.
00:08	In this tutorial we will, Demonstrate Membrane Channels, PhET simulation.
00:16	Here I am using Ubuntu Linux OS version 14.04 Java version 1.7.0
00:29	Firefox Web Browser version 53.02.2
00:35	To follow this tutorial, learner should be familiar with topics in high school biology.
00:43	Using Membrane Channels simulation, we will learn To predict movement of particles through the membrane
00:52	Types of channels present on the membrane
00:56	To predict the rate of diffusion based on the number and type of channels present
01:03	About Membrane Channels Membrane channels are proteins.
01:10	They allow passive transport of solute across a membrane.
01:15	The solute moves by simple diffusion through the membrane.
01:20	Solute moves from the region of higher concentration to the region of lower concentration.
01:27	The diffusion continues until the two compartments have equal concentrations.
01:34	Two types of channels are found in membranes,
01:39	Leakage channels and Gated channels. Leakage channels are always open.
01:47	Gated channels open in response to some stimulus.
01:53	Use the given link to download the simulation.
01:58	I have already downloaded Membrane Channels simulation to my Downloads folder.
02:05	To run the simulation, open the terminal. At the prompt type, cd space Downloads and press Enter.
02:18	Then type, java space hyphen jar space membrane hyphen channels_en.jar and press Enter.
02:32	Membrane Channels simulation opens.
02:36	This is the interface of Membrane Channels simulation.
02:41	The simulation window has two compartments separated by a membrane.
02:48	Each compartment has a solute pump. Each pump has two different types of solute particles.
02:58	Particles are represented as green circles and blue diamonds.
03:04	By default green circle is selected in the upper compartment. Blue diamond is selected in the lower compartment.
03:15	We can select the particle by clicking on the radio button next to the particle.
03:21	Click on the red button, to release a single particle into the compartment.
03:27	Two different kinds of channels are provided at the bottom,
03:32	Leakage channels and Gated channels. Drag and drop to add channels on the membrane.
03:43	Gated channels can be opened and closed using the buttons on the right-pannel.
03:50	Use the Play/Pause button to start and pause the simulation.
03:56	Step Button is activated when Play/Pause button is on Play mode. There is a slider to change the Sim speed from Slow to Fast.
04:08	There is a check-box on the right panel to show the concentrations of particles. Click on the Show Concentrations check-box.
04:19	Bar graphs showing concentrations for each compartment appear on the screen.
04:26	Click on Clear Particles button, to clear the particles present in the compartment.
04:33	To reset the simulation, click on Reset All button.
04:38	A message appears to prompt you to confirm the reset all settings.
04:44	Click on Yes button.
04:47	Click on Play button to play the simulation.
04:51	In the lower compartment, select blue particle.
04:56	Click on the red button to add blue particles to the compartment.
05:01	Click the red button 10 times to add 10 blue particles to the compartment.
05:11	Place 2 blue leakage channels on the membrane. The blue particles pass through the channel to the upper compartment.
05:22	Wait for a few seconds. Note the number of blue particles in the upper compartment.
05:30	The particles move in both directions through the channels. The diffusion of the particles continues.
05:39	After sometime the particles in both the compartments are almost equal. Click on Pause button to pause the simulation.
05:49	Click on Show Concentrations check-box.
05:53	Concentrations of particles in each compartment is represented as a bar graph.
06:00	Click on Play button to play the simulation.
06:04	Place one green Leakage Channel on the membrane.
06:09	Observe that blue particles do not pass through the green channel.
06:15	Now add 10 green particles to the lower compartment.
06:20	Click on the radio button next to the green particle.
06:25	Click the red button 10 times to add 10 green particles.
06:32	Observe the movement of the particles. Notice that the green particles do not pass through the blue channels.
06:42	They pass through the green channel only. This shows that, the channels are selective.
06:50	They only allow a particular particle to pass through them.
06:55	After sometime equilibrium is reached. Click on Pause button to pause the simulation.
07:03	Note that at this point concentration of the particles in both the compartments are almost same.
07:11	Click on Play button. The particles continue to move in both the directions to maintain the equilibrium.
07:20	Click on Reset All button. Click Yes to confirm the reset all settings.
07:27	Add 20 green particles to the upper compartment by clicking 20 times.
07:37	In the lower compartment, select blue particles radio button.
07:42	Add 20 blue particles to the lower compartment.
07:50	Place one each blue and green gated channel on the membrane.
07:57	Click on blue Open button on the right panel.
08:01	On the membrane, blue channel opens.
08:05	Blue particles move through the Gated channel in both the directions.
08:10	Click on Show Concentrations check-box. Wait until equilibrium is reached.
08:19	Green particles do not pass through the Blue gated channel, hence remain in the upper compartment.
08:28	Observe that there are no green particles in the lower compartment.
08:34	Now click on the green Open button on the right panel. On the membrane, green channel opens.
08:43	Green particles pass through the green gated channel to the lower compartment.
08:49	Equilibrium is reached after a few minutes.
08:55	Next, click on green Close button to close the green gated channel.
09:01	Observe the movement of particles. Notice that now only blue particles move between the compartments.
09:11	Green particles do not cross the compartments, as they cannot pass through blue channel.
09:18	This is how solute or ions diffuse through the membrane in real cells.
09:29	Lets Summarize, In this tutorial we have learnt, How to use Membrane Channels, PhET Simulation.
09:38	We have also learnt, To predict movement of particles through the membrane
09:44	Types of channels present on the membrane
09:48	To predict the rate of diffusion based on the number and type of channels present
09:55	As an assignment Fill the upper and lower compartments with equal number of blue and green particles.
10:05	Add gated channels of both colors on the membrane.
10:10	Note if the diffusion rate increases with increase in number of channels. Give Explanation.
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10:48	This project is partially funded by Pandit Madan Mohan Malaviya National Mission on Teachers and Teaching.
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11:09	This tutorial is contributed by Snehalatha Kaliappan and Meenal Ghoderao from IIT Bombay. Thank you for joining.

Contributors and Content Editors

Nancyvarkey, PoojaMoolya