facilitated diffusion

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lara
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facilitated diffusion

Post by lara » Mon Jan 16, 2006 11:34 am

how do the carrier proteins obtain energy for conformational change in faciilitated diffusion??

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victor
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Post by victor » Mon Jan 16, 2006 12:53 pm

they use ATP and metabolize it into ADP..
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Dr.Stein
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Post by Dr.Stein » Tue Jan 17, 2006 3:37 am

Naah! It doesn't include ATP. The one that using ATP conversion as its energy is the active transport. Facilitated diffusion is a kind of passive transport. The only energy involved is kinetic energy from the moving molecules 8)

Victor: ATP to ADP is not a metabolism process, it is a conversion :evil: :)
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Post by 2810712 » Tue Jan 17, 2006 6:23 am

i think the complete process is spotaneous [ the free energy change is negative] but it might require some activation energy kind of thing to change the conformation... the collision of the to-be-passed molecule may be providing enough energy.

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victor
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Post by victor » Tue Jan 17, 2006 11:52 am

hehe..sorry bout that..I misunderstood the question..:oops:
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MrMistery
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Post by MrMistery » Tue Jan 17, 2006 6:54 pm

Where there are 2 kinds of facilitated diffusion: through ion channels and permeases. Ion channels can be opened/closed whenever the cell wants, by attaching/detaching an external substance from it. it does not require activation energy simply because the protein "opens itself" when the substance is gone, by electrostatic forces.
Now, permeases function through a different mechanism known as the ping-pong mechanism. the 2 conformations of the protein are named PING(when the opening is on the inside) and PONG(when the opening is on the outside). When the substance transported binds to one side of the protein it causes a change in 3d conformation(like before, through electrostatic forces) and shifts to the other conformation. then the substance is released according to concentration gradient
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