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Secondary active transport

Discussion in 'MCAT Study Question Q&A' started by Deepa100, Jun 12, 2008.

  1. Deepa100

    Deepa100 Junior Member 10+ Year Member

    Aug 24, 2006
    Can this happen in both directions? i.e, in the direction of Na+ active transport by the ATPase (out of the cell) or in the opposite direction (into the cell)?
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  3. unsung

    unsung 10+ Year Member

    Mar 12, 2007
    Whatever's being transported has to go against the concentration gradient. So depending on whether the concentration gradient is lower inside the cell or out, that would determine the direction of the active transport. But at any given concentration gradient/situation, the active transport could only go in one direction.

    But, I don't believe the concentration gradient of the thing being transported has to go in the same direction as the Na+ concentration gradient.... symport/antiport both possible. Somebody correct me if I'm wrong.
  4. Vihsadas

    Vihsadas No summer Moderator Emeritus Lifetime Donor Classifieds Approved 5+ Year Member

    Oct 17, 2007
    An Igloo
    True, the only requirement for secondary active transport is that the "energy" of transport comes from another ion/molecule's (usually sodium's) concentration gradient. If you have the movement of one ion down its concentration gradient coupled with the movement of another ion against its concentration (regardless of the direction of transport) that is secondary active transport.
  5. supertrooper66

    supertrooper66 Banned

    Apr 28, 2008
    yeah, either direction is secondary active transport. symport is secondary active transport in same direction and antiport is samething but in opposite directions. both symport+antiport use the energy gradient made from _____ passive transport to fuel their own active transport.
  6. Deepa100

    Deepa100 Junior Member 10+ Year Member

    Aug 24, 2006
    Great, thanks!

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