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Suppose a plant cell wants to take something out of its central vacuole. Some specific substance. Well if the vacuole is a bit of a soup of water and other dissolved substances, how does the cell get some specific substance out? Without letting any of the water/solution into the vesicle that's budding off? Or do they just let the solution right in?

Clarification: Since a vacuole is full of water and other dissolved substances, wouldn't that solution get into a budding vesicle? How is this prevented? Is it prevented?

When the cell is creating a vesicle, it starts pinching off part of the membrane, correct? My question is how the solution in the vacuole stays out of the vesicle, if it does at all.

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  • $\begingroup$ could u pls clarify this part:Without letting any of the water/solution into the vesicle that's budding off? perhaps any research done on your part...that would be helpful. $\endgroup$ – user 33690 Aug 1 '17 at 7:36
  • $\begingroup$ Generally the vesicle budding off will contain the fluid from the organelle it comes from, plus it's cargo. The vesicle can then be modified, e.g. pH changed once it is separated from the original organelle. $\endgroup$ – Oliver Houston Aug 1 '17 at 11:23
  • $\begingroup$ @alpha When I wrote my answer I was not sure about your question... now, after the second edit (which you wrote after accepting my answer), I'm even less sure! What "vesicle" are you referring to? What do you mean by "how the solution in the vacuole stays out of the vesicle"? $\endgroup$ – user24284 Aug 1 '17 at 23:48
  • $\begingroup$ Sorry! I'm confusing myself too. So, I was told that a vacuole will form a vesicle (like the Golgi apparatus) when it's transporting substances out of it. I want to know how specific substances are transported out, without any water or other liquid in the vacuole getting into the vesicle. But I was also unsure whether or not the cell cares if this liquid gets in the vesicle in the first place. Does that help at all? Sorry again! Thank you! $\endgroup$ – alpha-tetramer Aug 1 '17 at 23:59
  • $\begingroup$ There is vesicular transport involved, but not to transport substances out of the vacuole. Have a look here: Plant vacuole morphology and vacuolar trafficking. $\endgroup$ – user24284 Aug 2 '17 at 0:59
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Your question is not entirely clear, even after the edit. However, I believe it's worth mentioning that the vacuole, just like any other membranar organelle1, is surrounded by a biomembrane.

Such biomembranes have transport proteins, which can be channels, carriers or pumps, and those transport proteins can determine which substances will get in/out of the vacuole, either down the electrochemical gradient (channels and carriers) or independent2 of it (pumps).

Here is a diagram showing the membrane of the vacuole with some transport proteins:

enter image description here

Therefore, since the cell can open or close a give gate or activate/deactivate a given pump (just like the transport proteins in the plasma membrane), that helps to explain how the cell decides what gets in or goes out the vacuolar lumen.

1: Unfortunately, there is not a consensus around the definition of organelle. The definition I use states that all organelles have a surrounding membrane (therefore, a ribosome is not an organelle), which renders the expression membranar organelle pleonastic.

2: It's very common reading that pumps will transport the substance against the electrochemical gradient. That's not correct. They will transport the substance independent of the gradient, that is, they can pump a substance against the gradient or down the gradient.

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