3/4 Biology question :)

[Romaboy]

Hey guys,

I just need help grasping a concept.
Say you have a potato cell & you place it in a solution with a high concentration of sucrose, water would move out of the cell, right?

But would sugar diffuse into the potato cell?

Just need help grasping diffusion/osmosis, thanks

[jasoN-]

sucrose won't passively diffuse into the cell, it's non-penetrating. water would however diffuse (by osmosis) out of the cell
if it was something like urea for example, then it would penetrate

[Romaboy]

So does that mean sucrose will only diffuse into the cell when the cell needs it?

& does this apply to all substances eg sucrose, salt, etc

[Panicmode]

So does that mean sucrose will only diffuse into the cell when the cell needs it?

& does this apply to all substances eg sucrose, salt, etc

Not quite. Sucrose passes through the plasma membrane by means of facilitated diffusion (still passive) with the concentration gradient. This means that if there is more sucrose outside the cell than inside, there will be a net movement of sucrose into the cell and vice-versa.

The same goes for other larger polar molecules that pass through via facilitated diffusion.

[duquesne9995]

will this facilitated diffusion of sucrose, or any diffusion for that matter, still happen if the cell is dead?

[LOLs99]

No I don't think so...common sense ques,yeah?

[lexitu]

will this facilitated diffusion of sucrose, or any diffusion for that matter, still happen if the cell is dead?

Yep it should, because it's not active in the process. Facilitated meaning it has the structures (e.g. protein channels) there to support passage in most cases.

(Correct me if I'm wrong by the way.) My first post on the Biology thread this year!

[Panicmode]

I'm with lex, as long as the structures are still there and functional I don't see why not.

This type of diffusion could also potentially cause cell death (due to toxic levels of certain substances entering the cell).