Active Transport

Posted by Professor Cram in Cell Membranes

Active Transport Video

Active Transport

Active transport is the mediated process of moving molecules and other substances across membranes.

Active transport differs from passive transport in that it utilizes chemical energy in the form of adenosine triphosphate, or ATP, to move molecules against the concentration gradient — from an area of lower concentration to an area of higher concentration.

There are two types of active transport:

Primary Active Transport

Primary active transport directly utilizes chemical energy to move molecules through a membrane.

The sodium-potassium pump, present in almost all animal cells, is an example of the use of primary active transport. It expends ATP energy to move sodium ions out of the cell and replace them with potassium ions.

This exchange leaves the interior of the cell more positively charged than the cell’s exterior. This means the sodium-potassium pump must overcome not only a concentration gradient but also an electrochemical gradient as well.

Secondary Active Transport

In secondary active transport, molecules are moved through a membrane as the direct result of the diffusion of another substance.

The sodium-calcium exchanger, or antiporter, uses the normal diffusion of sodium ions into the cell to power the transport of calcium out of the cell (and across a higher concentration gradient).

In another example, the glucose symporter uses the normal diffusion of sodium ions into the cell to piggyback the transport of glucose into the cell as well.



13 Responses to “Active Transport”

  1. sunita maharjan says:

    pliz give correct answer

  2. Aaron says:

    Water does not passively pass through the cell membrane. They are polar molecules, and the only circumstance under which they can pass through the membrane alone is if it has a large amount of energy and the molecule is forced through the membrane. Water actually passes through proteins called Aquaporins, which allows diffusion with no energy -> passive diffusion

  3. Billy-Joe says:


  4. Mrs.PhD says:

    Water passes through the cell membrane through osmosis which is a type of passive transport, hence no energy is needed, therefore it does passively pass through the plasma/cell membrane.

  5. Win on Qubids says:

    Great blog 9/10! Bookmarked :)

  6. Karl Zerby says:

    Dieser Schriften, da wird mir der gelangweilte Individuum jetzt schon huldigen, hat vor … nichtmal verschmelzen Aussage, er ist markant sinnentleert plus hat obgleich sich charakter auch chip eigene Bedeutungsarmut zum Punkt, unter anderem nichteinmal darin meinen er, das hättest du anscheinend gerne! er ist im Ãœbrigen unter Zuhilfenahme von Zuversicht der schlechteste Lyrics, den persönlichkeit jemals gelesen habe.

  7. transport ponadgabarytowy says:

    This is a great tip particularly to those fresh to the blogosphere.
    Brief but very precise information… Appreciate your sharing this one.
    A must read post!

  8. seo services says:

    226242292431321736885445222252 965135305409195 seo 4331221325282209018222 company 224227422160909545. 224127 seo agency 930892382903194 blue 32 68668781692704259434316412220 seo company 059139 5651585593034585696 77828.224373 :)

  9. says:

    Yes! Finally someone writes about best wordpress plugins.

  10. Fray says:

    Yooo. Don’t say water easiely passes through. Only small water molecules pass by at a particular time which is under passive transport as osmosis.
    The reason why only small molecules of H2O pass through is because that is a phospholipid layer and it is hyrophobic.

  11. Sydney Zepp says:

    I just added this blog to my google reader, excellent stuff. Can not get enough!

  12. Gwenn Seewald says:

    Throughout this awesome design of things you actually secure a B+ just for effort. Where you actually lost everybody was first in your facts. As they say, the devil is in the details… And it could not be much more accurate right here. Having said that, allow me reveal to you just what exactly did give good results. Your article (parts of it) can be really convincing and that is probably the reason why I am taking the effort in order to comment. I do not really make it a regular habit of doing that. Second, although I can easily see a leaps in reasoning you come up with, I am definitely not certain of how you seem to connect the ideas which make the actual conclusion. For right now I shall yield to your point however trust in the future you actually connect your facts much better.

  13. Vida Palumbo says:

    Fantastic items from you, man. I have take into accout your stuff prior to and you’re just extremely great. I actually like what you’ve got right here, really like what you’re stating and the best way through which you assert it. You are making it entertaining and you still care for to stay it smart. I cant wait to read far more from you. This is actually a terrific web site.

Leave a Reply