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

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||'''Time'''
||'''Narration'''

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|| 00:01
|| Welcome to this spoken tutorial on '''Membrane Channels PhET simulation'''. 

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|| 00:08
|| In this tutorial we will, Demonstrate '''Membrane Channels''', '''PhET simulation'''.

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|| 00:16
|| Here I am using Ubuntu Linux OS version 14.04

Java version 1.7.0

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|| 00:29
|| Firefox Web Browser version 53.02.2

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|| 00:35
|| To follow this tutorial, learner should be familiar with topics in high school biology.

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|| 00:43
|| Using '''Membrane Channels simulation''', we will learn 

To predict movement of particles through the membrane

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|| 00:52
|| Types of '''channels''' present on the membrane 

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|| 00:56
||  To predict the rate of diffusion based on the number and type of '''channels''' present

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|| 01:03
|| About '''Membrane Channels'''

'''Membrane channels''' are proteins.

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|| 01:10
|| They allow passive transport of solute across a membrane.

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|| 01:15
|| The solute moves by simple diffusion through the membrane. 

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|| 01:20
|| Solute moves from the region of higher concentration to the region of lower concentration.

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|| 01:27
|| The diffusion continues until the two compartments have equal concentrations.

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||01:34
|| Two types of '''channels''' are found in membranes,

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|| 01:39
|| '''Leakage channels''' and '''Gated channels'''.

'''Leakage channels''' are always open.

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|| 01:47
|| '''Gated channels''' open in response to some stimulus.

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|| 01:53
|| Use the given link to download the '''simulation'''.

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|| 01:58
|| I have already downloaded '''Membrane Channels simulation''' to my '''Downloads''' folder.

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|| 02:05
|| To run the '''simulation''', open the '''terminal'''.

At the prompt type, '''cd space Downloads''' and press '''Enter'''.

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|| 02:18
|| Then type, '''java space hyphen jar space membrane hyphen channels_en.jar''' and press '''Enter'''.

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|| 02:32
|| '''Membrane Channels simulation''' opens.

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|| 02:36
|| This is the interface of '''Membrane Channels simulation'''.

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|| 02:41
|| The '''simulation''' window has two compartments separated by a membrane.

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|| 02:48
|| Each compartment has a solute pump.

Each pump has two different types of solute particles.

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|| 02:58
|| Particles are represented as green circles and blue diamonds.

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||03:04
|| By default green circle is selected in the upper compartment.

Blue diamond is selected in the lower compartment.

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|| 03:15
|| We can select the particle by clicking on the radio button next to the particle.

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|| 03:21
|| Click on the red button, to release a single particle into the compartment.

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|| 03:27
|| Two different kinds of '''channels''' are provided at the bottom,

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|| 03:32
|| '''Leakage channels''' and '''Gated channels'''.

Drag and drop to add '''channels''' on the membrane.

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|| 03:43
|| '''Gated channels''' can be opened and closed using the buttons on the right-pannel.

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|| 03:50
|| Use the '''Play/Pause button''' to start and pause the '''simulation'''.

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|| 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'''.

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|| 04:08
|| There is a check-box on the right panel to show the concentrations of particles. 

Click on the '''Show Concentrations''' check-box.

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|| 04:19
|| Bar graphs showing concentrations for each compartment appear on the screen.

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|| 04:26
|| Click on '''Clear Particles''' button, to clear the particles present in the compartment.

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|| 04:33
|| To reset the '''simulation''', click on '''Reset All''' button. 

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|| 04:38
|| A message appears to prompt you to confirm the reset all settings.

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|| 04:44
|| Click on '''Yes''' button.

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|| 04:47
|| Click on '''Play''' button to play the '''simulation'''.

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|| 04:51
|| In the lower compartment, select blue particle.

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|| 04:56
|| Click on the red button to add blue particles to the compartment.

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|| 05:01
|| Click the red button 10 times to add 10 blue particles to the compartment. 

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|| 05:11
|| Place 2 blue '''leakage channels''' on the membrane.

The blue particles pass through the '''channel''' to the upper compartment.

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|| 05:22
|| Wait for a few seconds. 

Note the number of blue particles in the upper compartment.

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|| 05:30
|| The particles move in both directions through the '''channels'''.

The diffusion of the particles continues. 

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|| 05:39
|| After sometime the particles in both the compartments are almost equal.

Click on '''Pause''' button to pause the '''simulation'''.

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|| 05:49
|| Click on '''Show Concentrations''' check-box.

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|| 05:53
|| Concentrations of particles in each compartment is represented as a bar graph.

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|| 06:00
|| Click on '''Play''' button to play the '''simulation'''.

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|| 06:04
|| Place one green '''Leakage Channel''' on the membrane.

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|| 06:09
|| Observe that blue particles do not pass through the green '''channel'''. 

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|| 06:15
|| Now add 10 green particles to the lower compartment.

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|| 06:20
|| Click on the radio button next to the green particle.

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|| 06:25
|| Click the red button 10 times to add 10 green particles.

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|| 06:32
|| Observe the movement of the particles.

Notice that the green particles do not pass through the blue '''channels'''.

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|| 06:42
|| They pass through the green '''channel''' only.

This shows that, the '''channels''' are selective.

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|| 06:50
|| They only allow a particular particle to pass through them.

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|| 06:55
|| After sometime equilibrium is reached.

Click on '''Pause''' button to pause the '''simulation'''.

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|| 07:03
|| Note that at this point concentration of the particles in both the compartments are almost same.

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|| 07:11
|| Click on '''Play''' button.

The particles continue to move in both the directions to maintain the equilibrium.

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|| 07:20
|| Click on '''Reset All''' button.

Click '''Yes''' to confirm the reset all settings.

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||07:27
|| Add 20 green particles to the upper compartment by clicking 20 times.

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|| 07:37
|| In the lower compartment, select blue particles radio button.

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|| 07:42
|| Add 20 blue particles to the lower compartment.

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|| 07:50
|| Place one each blue and green '''gated channel''' on the membrane.

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|| 07:57
|| Click on blue '''Open''' button on the right panel. 

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|| 08:01
|| On the membrane, blue '''channel''' opens.

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|| 08:05
|| Blue particles move through the '''Gated channel''' in both the directions.

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|| 08:10
|| Click on '''Show Concentrations''' check-box.

Wait until equilibrium is reached.

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|| 08:19
|| Green particles do not pass through the Blue '''gated channel''', hence remain in the upper compartment.

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|| 08:28
|| Observe that there are no green particles in the lower compartment.

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|| 08:34
|| Now click on the green '''Open''' button on the right panel.

On the membrane, green '''channel''' opens.

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|| 08:43
|| Green particles pass through the green '''gated channel''' to the lower compartment.

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|| 08:49
|| Equilibrium is reached after a few minutes.

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|| 08:55
|| Next, click on green '''Close''' button to close the green '''gated channel'''.

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|| 09:01
|| Observe the movement of particles. Notice that now only blue particles move between the compartments.

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|| 09:11
|| Green particles do not cross the compartments, as they cannot pass through blue '''channel'''.

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|| 09:18
|| This is how solute or ions diffuse through the membrane in real cells.

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|| 09:29
|| Lets Summarize, In this tutorial we have learnt, 

How to use '''Membrane Channels''', '''PhET Simulation'''.

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|| 09:38
|| We have also learnt, To predict movement of particles through the membrane 

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|| 09:44
||  Types of '''channels''' present on the membrane

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|| 09:48
|| To predict the rate of diffusion based on the number and type of '''channels''' present

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|| 09:55
|| As an assignment

Fill the upper and lower compartments with equal number of blue and green particles.

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|| 10:05
|| Add '''gated channels''' of both colors on the membrane.

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|| 10:10
|| Note if the diffusion rate increases with increase in number of '''channels'''.

Give Explanation.

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|| 10:20
|| The video at the following link summarizes the Spoken Tutorial project.

Please download and watch it.

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|| 10:29
|| The '''Spoken Tutorial Project''' team: conducts workshops using spoken tutorials and gives certificates on passing online tests.

For more details, please write to us.

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||10:43
|| Please post your timed queries on this forum.

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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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|| 10:56
|| The Spoken Tutorial Project is funded by '''NMEICT, MHRD,''' '''Government of India'''.

More information on this Mission is available at this link. 

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|| 11:09
|| This tutorial is contributed by Snehalatha Kaliappan and Meenal Ghoderao from IIT Bombay.

Thank you for joining. 

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