Passive transport: Difference between revisions
No edit summary |
added text, added link |
||
| Line 1: | Line 1: | ||
Passive transport is the movement of molecules across the [[Plasma membrane|plasma membrane down]] the concentration gradient without the input of energy<ref>↑ Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2008) Molecular biology of the cell, 5th edition, Garland science.</ref>. | Passive transport is the movement of molecules across the [[Plasma membrane|plasma membrane down]] the concentration gradient without the input of energy<ref>↑ Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2008) Molecular biology of the cell, 5th edition, Garland science.</ref>, therefore the concentration determines the direction and rate of transport across the membrane. | ||
There are two types of passive transport: | There are two types of passive transport: | ||
| Line 9: | Line 9: | ||
*[[Facilitated diffusion|Facilitated diffusion]] | *[[Facilitated diffusion|Facilitated diffusion]] | ||
Many [[Molecules|molecules]] ([[Polar|polar]], charged, large, and [[Hydrophilic|hydrophilic]]) can not cross the [[Plasma membrane|plasma membrane]], so the passage of these molecules is facilitated by membrane transport proteins (channel or carrier [[Proteins|proteins]]) <ref>↑ Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2008) Molecular biology of the cell, 5th edition, Garland science.</ref>. <br> | Many [[Molecules|molecules]] ([[Polar|polar]], charged, large, and [[Hydrophilic|hydrophilic]]) can not cross the [[Plasma membrane|plasma membrane]], so the passage of these molecules is facilitated by membrane transport proteins (channel or carrier [[Proteins|proteins]]) <ref>↑ Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2008) Molecular biology of the cell, 5th edition, Garland science.</ref>. An advantage of facilitated diffusion is that there is potential for movement across the membrane in either direction of the concentration gradient. <br> | ||
A carrier that transports only one substrate during facilitated diffusion is called a [[Uniporter|uniporter]]. | |||
=== References: === | === References: === | ||
<references /> | <references /> | ||
Revision as of 16:35, 4 December 2016
Passive transport is the movement of molecules across the plasma membrane down the concentration gradient without the input of energy[1], therefore the concentration determines the direction and rate of transport across the membrane.
There are two types of passive transport:
Non-polar, water, small, hydrophobic molecules can cross the membrane by simple diffusion
Many molecules (polar, charged, large, and hydrophilic) can not cross the plasma membrane, so the passage of these molecules is facilitated by membrane transport proteins (channel or carrier proteins) [2]. An advantage of facilitated diffusion is that there is potential for movement across the membrane in either direction of the concentration gradient.
A carrier that transports only one substrate during facilitated diffusion is called a uniporter.